Composite Shape Calculator
Calculate the area of complex shapes with ease.
Online Composite Shape Area Calculator
This calculator helps you find the area of composite shapes by breaking them down into simpler, standard geometric figures like rectangles, triangles, circles, and semicircles. Enter the dimensions for each component shape.
Rectangle
Triangle
Circle
Semicircle
Enter the length of the first rectangle.
Enter the width of the first rectangle.
Rectangle
Triangle
Circle
Semicircle
Enter the length of the second rectangle.
Enter the width of the second rectangle.
None
Rectangle
Triangle
Circle
Semicircle
Enter the length of the third rectangle.
Enter the width of the third rectangle.
Calculation Results
—Area Shape 1: —
Area Shape 2: —
Area Shape 3: —
Total Area: —
Total Area = Area(Shape 1) + Area(Shape 2) + Area(Shape 3)
Composite Shape Area Data
Shape 1 Area
Shape 2 Area
Shape 3 Area
Total Area
| Component | Type | Dimensions | Area (units²) |
|---|---|---|---|
| Shape 1 | — | — | — |
| Shape 2 | — | — | — |
| Shape 3 | — | — | — |
| Total Composite Area | — | ||
What is a Composite Shape?
A composite shape calculator is a tool designed to help users determine the area of complex geometric figures that are formed by combining two or more simpler shapes. Unlike basic shapes like squares, circles, or triangles, composite shapes don't have a single, direct formula for their area. Instead, they are constructed from these fundamental shapes. Understanding composite shapes is crucial in various fields, from architecture and engineering to everyday tasks like calculating paint needed for a room with alcoves or the amount of fabric for a custom design.
Who should use it? Students learning geometry, architects, engineers, designers, DIY enthusiasts, and anyone needing to calculate the area of irregular or combined shapes will find this tool invaluable. It simplifies complex calculations, saving time and reducing the potential for errors.
Common misconceptions about composite shapes include assuming they always involve simple additions of areas. Sometimes, a composite shape might involve subtracting the area of one shape from another (e.g., a donut shape or a shape with a hole). This calculator focuses on additive composite shapes for simplicity, but the principle of breaking down complexity remains the same.
Composite Shape Area Formula and Mathematical Explanation
The fundamental principle behind calculating the area of a composite shape is decomposition. We break down the complex shape into its constituent simpler shapes. The total area is then the sum of the areas of these individual components.
Step-by-step derivation:
- Identify the simpler geometric shapes (e.g., rectangles, triangles, circles) that make up the composite shape.
- Measure or determine the necessary dimensions (length, width, radius, base, height) for each of these simpler shapes.
- Apply the standard area formula for each identified shape.
- Sum the areas of all the individual shapes to find the total area of the composite shape.
Variable explanations:
The specific variables depend on the shapes involved. For common shapes:
- Rectangle: Length (L), Width (W)
- Triangle: Base (b), Height (h)
- Circle: Radius (r)
- Semicircle: Radius (r)
Area Formulas for Component Shapes:
- Area of Rectangle = L × W
- Area of Triangle = 0.5 × b × h
- Area of Circle = π × r²
- Area of Semicircle = 0.5 × π × r²
The Composite Shape Area Formula:
Total Area = Area(Shape 1) + Area(Shape 2) + … + Area(Shape N)
Variables Table
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| L, W | Length, Width (Rectangle) | Length units (e.g., meters, feet, inches) | 0.1 to 1000+ |
| b, h | Base, Height (Triangle) | Length units | 0.1 to 1000+ |
| r | Radius (Circle, Semicircle) | Length units | 0.1 to 1000+ |
| π (Pi) | Mathematical constant | Unitless | Approximately 3.14159 |
| Area | Calculated area of a shape | Square units (e.g., m², ft², in²) | 0.01 to 1,000,000+ |
Practical Examples (Real-World Use Cases)
Let's illustrate with a couple of examples using our composite shape calculator.
Example 1: A House Outline (Simplified)
Imagine a simple house shape consisting of a rectangular base and a triangular roof.
- Shape 1: Rectangle (Main House Body)
- Dimensions: Length = 10 meters, Width = 8 meters
- Shape 2: Triangle (Roof)
- Dimensions: Base = 10 meters (matching the rectangle's length), Height = 4 meters
Calculation:
- Area of Rectangle = 10 m × 8 m = 80 m²
- Area of Triangle = 0.5 × 10 m × 4 m = 20 m²
- Total Area = 80 m² + 20 m² = 100 m²
Interpretation: The total floor area plus the roof area (if considered as a flat projection) is 100 square meters. This could be useful for estimating roofing materials or calculating the overall footprint.
Example 2: A Window Design
Consider a window composed of a rectangle with a semicircle on top.
- Shape 1: Rectangle
- Dimensions: Length = 5 feet, Width = 3 feet
- Shape 2: Semicircle
- Dimensions: The diameter of the semicircle matches the width of the rectangle (5 feet). So, the Radius (r) = 5 feet / 2 = 2.5 feet.
Calculation:
- Area of Rectangle = 5 ft × 3 ft = 15 ft²
- Area of Semicircle = 0.5 × π × (2.5 ft)² ≈ 0.5 × 3.14159 × 6.25 ft² ≈ 9.82 ft²
- Total Area = 15 ft² + 9.82 ft² = 24.82 ft²
Interpretation: The total area of the window design is approximately 24.82 square feet. This helps in ordering the correct amount of glass or calculating heat transfer through the window.
How to Use This Composite Shape Calculator
Using our composite shape calculator is straightforward. Follow these steps:
- Identify Component Shapes: Look at your complex shape and break it down into basic geometric figures (rectangles, triangles, circles, semicircles).
- Select Shape Types: Use the dropdown menus for "Component Shape 1 Type", "Component Shape 2 Type", and optionally "Component Shape 3 Type" to select the shapes you identified.
- Input Dimensions: For each selected shape, enter its required dimensions (e.g., length and width for a rectangle, base and height for a triangle, radius for a circle) into the corresponding input fields. Ensure you are using consistent units.
- Calculate: Click the "Calculate Area" button.
How to read results:
- The calculator will display the calculated area for each individual component shape (Area Shape 1, Area Shape 2, Area Shape 3).
- The "Main Result" (Total Area) will show the sum of these individual areas, representing the total area of your composite shape.
- The table provides a clear breakdown of each shape's type, dimensions, and calculated area.
- The chart visually represents the contribution of each shape's area to the total.
Decision-making guidance: The calculated total area can inform decisions about material quantities (paint, flooring, fabric), space planning, structural load calculations, and more. For instance, if calculating the area to be tiled, the total area directly tells you how many tiles you need.
Key Factors That Affect Composite Shape Results
While the calculation itself is straightforward addition, several factors influence the accuracy and interpretation of the results:
- Accuracy of Dimensions: The most critical factor. Even small measurement errors in length, width, base, height, or radius can lead to significant differences in the final area calculation, especially for large or complex shapes. Precise measurement is key.
- Correct Identification of Shapes: Misidentifying a component shape (e.g., treating a trapezoid as a rectangle) will lead to incorrect area calculations for that part and thus the total.
- Consistent Units: Ensure all dimensions are entered in the same units (e.g., all in meters, or all in feet). Mixing units (e.g., length in meters and width in centimeters) will produce nonsensical results. The output area will be in the square of the input unit.
- Completeness of Decomposition: Ensure all parts of the composite shape are accounted for. If a section is missed, the calculated area will be an underestimation.
- Handling of Subtractive Areas: This calculator assumes additive areas. If your composite shape involves holes or cutouts (e.g., a courtyard within a building footprint), you would need to calculate the area of the cutout shape and subtract it from the total. This requires a modified approach or a more advanced calculator.
- Curved vs. Straight Edges: Accurately measuring curved segments (like arcs or complex curves) can be challenging. This calculator handles standard circles and semicircles; more complex curves would require calculus or specialized tools.
- Scale and Precision: For very large structures (like land plots) or very small components (like microchips), the required precision of measurements and calculations increases. Ensure your input values reflect the necessary level of detail.
Frequently Asked Questions (FAQ)
What is a composite shape?
A composite shape, also known as a compound shape, is a shape made up of two or more simpler geometric shapes. Examples include a rectangle with a triangle on top, or a circle with a smaller circle removed from its center.
How do I calculate the area of a composite shape?
You calculate the area by dividing the composite shape into its basic component shapes, calculating the area of each individual shape using standard formulas, and then summing these areas together. If the shape involves cutouts, you subtract the area of the cutout.
Can this calculator handle shapes with holes?
This specific calculator is designed for additive composite shapes (where areas are added). For shapes with holes or cutouts, you would need to calculate the area of the main shape and then subtract the area of the hole, which would require separate calculations or a more advanced tool.
What units should I use for dimensions?
You can use any unit (e.g., meters, feet, inches, cm), but it's crucial to be consistent. All dimensions entered for the component shapes should be in the same unit. The resulting area will be in the square of that unit (e.g., square meters, square feet).
What if my shape has more than three components?
This calculator supports up to three component shapes. For shapes with more components, you can adapt the principle: calculate the area of each additional shape and add it to the total calculated by this tool.
What is Pi (π)?
Pi (π) is a mathematical constant approximately equal to 3.14159. It represents the ratio of a circle's circumference to its diameter and is fundamental in calculating the area and circumference of circles and related shapes.
How accurate is the calculator?
The calculator's accuracy depends entirely on the accuracy of the input dimensions you provide and the correctness of the standard geometric formulas used. The calculations themselves are precise based on the inputs.
Can I use this for 3D shapes?
No, this calculator is specifically for calculating the 2D area of composite shapes. Calculating the volume or surface area of 3D composite shapes requires different formulas and tools.
Related Tools and Internal Resources
- Composite Shape Calculator Our primary tool for calculating the area of combined geometric figures.
- Basic Geometry Formulas Guide A comprehensive reference for formulas of common shapes like squares, triangles, and circles.
- Area and Perimeter Calculator Calculate both area and perimeter for standard shapes.
- 3D Volume Calculator Calculate the volume of various three-dimensional shapes.
- Unit Converter Tool Easily convert measurements between different units (e.g., meters to feet).
- Tips for Construction Math Practical advice for applying mathematical concepts in building and design projects.
Enter the length of rectangle ${shapeNum}.
Enter the width of rectangle ${shapeNum}.
`;
} else if (selectedType === 'triangle') {
htmlContent = `
Enter the base of triangle ${shapeNum}.
Enter the height of triangle ${shapeNum}.
`;
} else if (selectedType === 'circle') {
htmlContent = `
Enter the radius of circle ${shapeNum}.
`;
} else if (selectedType === 'semicircle') {
htmlContent = `
Enter the radius of semicircle ${shapeNum}.
`;
}
paramsDiv.innerHTML = htmlContent;
if (selectedType === 'none') {
paramsDiv.style.display = 'none';
} else {
paramsDiv.style.display = 'block';
}
}
function updateCalculator() {
updateShapeParams(1);
updateShapeParams(2);
var shape3TypeSelect = document.getElementById('shape3Type');
var shape3ParamsDiv = document.getElementById('shape3Params');
if (shape3TypeSelect.value === 'none') {
shape3ParamsDiv.style.display = 'none';
} else {
shape3ParamsDiv.style.display = 'block';
updateShapeParams(3);
}
calculateArea(); // Recalculate on type change
}
function calculateArea() {
var area1 = 0;
var area2 = 0;
var area3 = 0;
var totalArea = 0;
var shape1Type = document.getElementById('shape1Type').value;
var shape2Type = document.getElementById('shape2Type').value;
var shape3Type = document.getElementById('shape3Type').value;
var validInputs = true;
// Shape 1 Calculations
if (shape1Type === 'rectangle') {
if (!validateInput('shape1_rect_length', 'shape1_rect_length_error') || !validateInput('shape1_rect_width', 'shape1_rect_width_error')) validInputs = false;
var length = parseFloat(document.getElementById('shape1_rect_length').value);
var width = parseFloat(document.getElementById('shape1_rect_width').value);
area1 = length * width;
} else if (shape1Type === 'triangle') {
if (!validateInput('shape1_tri_base', 'shape1_tri_base_error') || !validateInput('shape1_tri_height', 'shape1_tri_height_error')) validInputs = false;
var base = parseFloat(document.getElementById('shape1_tri_base').value);
var height = parseFloat(document.getElementById('shape1_tri_height').value);
area1 = 0.5 * base * height;
} else if (shape1Type === 'circle') {
if (!validateInput('shape1_circ_radius', 'shape1_circ_radius_error')) validInputs = false;
var radius = parseFloat(document.getElementById('shape1_circ_radius').value);
area1 = pi * radius * radius;
} else if (shape1Type === 'semicircle') {
if (!validateInput('shape1_semi_radius', 'shape1_semi_radius_error')) validInputs = false;
var radius = parseFloat(document.getElementById('shape1_semi_radius').value);
area1 = 0.5 * pi * radius * radius;
}
// Shape 2 Calculations
if (shape2Type === 'rectangle') {
if (!validateInput('shape2_rect_length', 'shape2_rect_length_error') || !validateInput('shape2_rect_width', 'shape2_rect_width_error')) validInputs = false;
var length = parseFloat(document.getElementById('shape2_rect_length').value);
var width = parseFloat(document.getElementById('shape2_rect_width').value);
area2 = length * width;
} else if (shape2Type === 'triangle') {
if (!validateInput('shape2_tri_base', 'shape2_tri_base_error') || !validateInput('shape2_tri_height', 'shape2_tri_height_error')) validInputs = false;
var base = parseFloat(document.getElementById('shape2_tri_base').value);
var height = parseFloat(document.getElementById('shape2_tri_height').value);
area2 = 0.5 * base * height;
} else if (shape2Type === 'circle') {
if (!validateInput('shape2_circ_radius', 'shape2_circ_radius_error')) validInputs = false;
var radius = parseFloat(document.getElementById('shape2_circ_radius').value);
area2 = pi * radius * radius;
} else if (shape2Type === 'semicircle') {
if (!validateInput('shape2_semi_radius', 'shape2_semi_radius_error')) validInputs = false;
var radius = parseFloat(document.getElementById('shape2_semi_radius').value);
area2 = 0.5 * pi * radius * radius;
}
// Shape 3 Calculations
if (shape3Type !== 'none') {
if (shape3Type === 'rectangle') {
if (!validateInput('shape3_rect_length', 'shape3_rect_length_error') || !validateInput('shape3_rect_width', 'shape3_rect_width_error')) validInputs = false;
var length = parseFloat(document.getElementById('shape3_rect_length').value);
var width = parseFloat(document.getElementById('shape3_rect_width').value);
area3 = length * width;
} else if (shape3Type === 'triangle') {
if (!validateInput('shape3_tri_base', 'shape3_tri_base_error') || !validateInput('shape3_tri_height', 'shape3_tri_height_error')) validInputs = false;
var base = parseFloat(document.getElementById('shape3_tri_base').value);
var height = parseFloat(document.getElementById('shape3_tri_height').value);
area3 = 0.5 * base * height;
} else if (shape3Type === 'circle') {
if (!validateInput('shape3_circ_radius', 'shape3_circ_radius_error')) validInputs = false;
var radius = parseFloat(document.getElementById('shape3_circ_radius').value);
area3 = pi * radius * radius;
} else if (shape3Type === 'semicircle') {
if (!validateInput('shape3_semi_radius', 'shape3_semi_radius_error')) validInputs = false;
var radius = parseFloat(document.getElementById('shape3_semi_radius').value);
area3 = 0.5 * pi * radius * radius;
}
}
if (!validInputs) {
document.getElementById('main-result').textContent = "–";
document.getElementById('areaShape1').textContent = "Area Shape 1: –";
document.getElementById('areaShape2').textContent = "Area Shape 2: –";
document.getElementById('areaShape3').textContent = "Area Shape 3: –";
document.getElementById('totalArea').textContent = "Total Area: –";
updateTableAndChart(0, 0, 0, 0, "", "", "");
return;
}
totalArea = area1 + area2 + area3;
document.getElementById('main-result').textContent = totalArea.toFixed(2);
document.getElementById('areaShape1').textContent = "Area Shape 1: " + area1.toFixed(2);
document.getElementById('areaShape2').textContent = "Area Shape 2: " + area2.toFixed(2);
document.getElementById('areaShape3').textContent = "Area Shape 3: " + (area3 > 0 ? area3.toFixed(2) : "–");
document.getElementById('totalArea').textContent = "Total Area: " + totalArea.toFixed(2);
updateTableAndChart(area1, area2, area3, totalArea, shape1Type, shape2Type, shape3Type);
}
function updateTableAndChart(area1, area2, area3, totalArea, type1, type2, type3) {
document.getElementById('tableShape1Type').textContent = type1.charAt(0).toUpperCase() + type1.slice(1);
document.getElementById('tableShape2Type').textContent = type2.charAt(0).toUpperCase() + type2.slice(1);
document.getElementById('tableShape3Type').textContent = type3 === 'none' ? '–' : type3.charAt(0).toUpperCase() + type3.slice(1);
var dims1 = "";
if (type1 === 'rectangle') dims1 = `L: ${document.getElementById('shape1_rect_length').value}, W: ${document.getElementById('shape1_rect_width').value}`;
else if (type1 === 'triangle') dims1 = `b: ${document.getElementById('shape1_tri_base').value}, h: ${document.getElementById('shape1_tri_height').value}`;
else if (type1 === 'circle') dims1 = `r: ${document.getElementById('shape1_circ_radius').value}`;
else if (type1 === 'semicircle') dims1 = `r: ${document.getElementById('shape1_semi_radius').value}`;
document.getElementById('tableShape1Dims').textContent = dims1;
var dims2 = "";
if (type2 === 'rectangle') dims2 = `L: ${document.getElementById('shape2_rect_length').value}, W: ${document.getElementById('shape2_rect_width').value}`;
else if (type2 === 'triangle') dims2 = `b: ${document.getElementById('shape2_tri_base').value}, h: ${document.getElementById('shape2_tri_height').value}`;
else if (type2 === 'circle') dims2 = `r: ${document.getElementById('shape2_circ_radius').value}`;
else if (type2 === 'semicircle') dims2 = `r: ${document.getElementById('shape2_semi_radius').value}`;
document.getElementById('tableShape2Dims').textContent = dims2;
var dims3 = "";
if (type3 !== 'none') {
if (type3 === 'rectangle') dims3 = `L: ${document.getElementById('shape3_rect_length').value}, W: ${document.getElementById('shape3_rect_width').value}`;
else if (type3 === 'triangle') dims3 = `b: ${document.getElementById('shape3_tri_base').value}, h: ${document.getElementById('shape3_tri_height').value}`;
else if (type3 === 'circle') dims3 = `r: ${document.getElementById('shape3_circ_radius').value}`;
else if (type3 === 'semicircle') dims3 = `r: ${document.getElementById('shape3_semi_radius').value}`;
}
document.getElementById('tableShape3Dims').textContent = type3 === 'none' ? '–' : dims3;
document.getElementById('tableArea1').textContent = area1 > 0 ? area1.toFixed(2) : '–';
document.getElementById('tableArea2').textContent = area2 > 0 ? area2.toFixed(2) : '–';
document.getElementById('tableArea3').textContent = area3 > 0 ? area3.toFixed(2) : '–';
document.getElementById('tableTotalArea').textContent = totalArea.toFixed(2);
// Chart Update
var ctx = document.getElementById('areaChart').getContext('2d');
if (window.areaChartInstance) {
window.areaChartInstance.destroy();
}
var chartData = {
labels: ['Shape 1', 'Shape 2', 'Shape 3'],
datasets: [{
label: 'Area Contribution',
data: [area1, area2, area3],
backgroundColor: [
'#ffc107', // Shape 1 color
'#17a2b8', // Shape 2 color
'#6f42c1' // Shape 3 color
],
borderColor: [
'#e0a800',
'#138496',
'#5a2e91'
],
borderWidth: 1
}]
};
// Add total area as a separate dataset or annotation if needed,
// but for a simple bar chart, showing components is usually clearer.
// For this example, we'll stick to component areas.
window.areaChartInstance = new Chart(ctx, {
type: 'bar',
data: chartData,
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'Area (units²)'
}
}
},
plugins: {
legend: {
display: false // Using custom legend
},
title: {
display: true,
text: 'Area Breakdown by Component'
}
}
}
});
}
function resetCalculator() {
document.getElementById('shape1Type').value = 'rectangle';
document.getElementById('shape1_rect_length').value = '10';
document.getElementById('shape1_rect_width').value = '5';
document.getElementById('shape2Type').value = 'rectangle';
document.getElementById('shape2_rect_length').value = '8';
document.getElementById('shape2_rect_width').value = '4';
document.getElementById('shape3Type').value = 'none';
updateCalculator(); // Update UI and recalculate
}
function copyResults() {
var mainResult = document.getElementById('main-result').textContent;
var area1 = document.getElementById('areaShape1').textContent;
var area2 = document.getElementById('areaShape2').textContent;
var area3 = document.getElementById('areaShape3').textContent;
var totalArea = document.getElementById('totalArea').textContent;
var formula = document.querySelector('#results .formula-explanation').textContent;
var assumptions = "Key Assumptions:\n";
var shape1Type = document.getElementById('shape1Type').value;
var shape2Type = document.getElementById('shape2Type').value;
var shape3Type = document.getElementById('shape3Type').value;
assumptions += `- Shape 1 Type: ${shape1Type}\n`;
if (shape1Type === 'rectangle') assumptions += ` Length: ${document.getElementById('shape1_rect_length').value}, Width: ${document.getElementById('shape1_rect_width').value}\n`;
else if (shape1Type === 'triangle') assumptions += ` Base: ${document.getElementById('shape1_tri_base').value}, Height: ${document.getElementById('shape1_tri_height').value}\n`;
else if (shape1Type === 'circle') assumptions += ` Radius: ${document.getElementById('shape1_circ_radius').value}\n`;
else if (shape1Type === 'semicircle') assumptions += ` Radius: ${document.getElementById('shape1_semi_radius').value}\n`;
assumptions += `- Shape 2 Type: ${shape2Type}\n`;
if (shape2Type === 'rectangle') assumptions += ` Length: ${document.getElementById('shape2_rect_length').value}, Width: ${document.getElementById('shape2_rect_width').value}\n`;
else if (shape2Type === 'triangle') assumptions += ` Base: ${document.getElementById('shape2_tri_base').value}, Height: ${document.getElementById('shape2_tri_height').value}\n`;
else if (shape2Type === 'circle') assumptions += ` Radius: ${document.getElementById('shape2_circ_radius').value}\n`;
else if (shape2Type === 'semicircle') assumptions += ` Radius: ${document.getElementById('shape2_semi_radius').value}\n`;
if (shape3Type !== 'none') {
assumptions += `- Shape 3 Type: ${shape3Type}\n`;
if (shape3Type === 'rectangle') assumptions += ` Length: ${document.getElementById('shape3_rect_length').value}, Width: ${document.getElementById('shape3_rect_width').value}\n`;
else if (shape3Type === 'triangle') assumptions += ` Base: ${document.getElementById('shape3_tri_base').value}, Height: ${document.getElementById('shape3_tri_height').value}\n`;
else if (shape3Type === 'circle') assumptions += ` Radius: ${document.getElementById('shape3_circ_radius').value}\n`;
else if (shape3Type === 'semicircle') assumptions += ` Radius: ${document.getElementById('shape3_semi_radius').value}\n`;
}
var textToCopy = `— Composite Shape Area Calculation —\n\n`
+ `Main Result (Total Area): ${mainResult}\n`
+ `${area1}\n`
+ `${area2}\n`
+ `${area3}\n`
+ `Formula Used: ${formula}\n\n`
+ `${assumptions}`;
navigator.clipboard.writeText(textToCopy).then(function() {
alert('Results copied to clipboard!');
}).catch(function(err) {
console.error('Failed to copy: ', err);
alert('Failed to copy results. Please copy manually.');
});
}
// Initialize FAQ toggles
document.addEventListener('DOMContentLoaded', function() {
var faqItems = document.querySelectorAll('.faq-item .faq-question');
faqItems.forEach(function(item) {
item.addEventListener('click', function() {
var faqItem = this.parentElement;
faqItem.classList.toggle('open');
});
});
// Initial setup and calculation
updateCalculator();
calculateArea(); // Ensure calculation on load
});
// Add Chart.js library dynamically if not present (for demonstration purposes)
// In a real WordPress setup, you'd enqueue this script properly.
if (typeof Chart === 'undefined') {
var script = document.createElement('script');
script.src = 'https://cdn.jsdelivr.net/npm/chart.js';
script.onload = function() {
// Re-initialize calculator after chart library is loaded
updateCalculator();
calculateArea();
};
document.head.appendChild(script);
} else {
// If Chart.js is already loaded, just ensure calculation happens
updateCalculator();
calculateArea();
}