Ratio and Proportion Calculator
body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f8f9fa;
color: #333;
line-height: 1.6;
margin: 0;
padding: 20px;
}
.loan-calc-container {
max-width: 800px;
margin: 30px auto;
background-color: #ffffff;
padding: 30px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}
h1, h2 {
color: #004a99;
text-align: center;
margin-bottom: 20px;
}
.input-group {
margin-bottom: 20px;
display: flex;
flex-wrap: wrap;
gap: 15px;
align-items: center;
}
.input-group label {
flex: 1 1 150px; /* Grow, shrink, basis */
min-width: 120px;
font-weight: bold;
color: #004a99;
}
.input-group input[type="number"],
.input-group select {
flex: 2 2 200px; /* Grow, shrink, basis */
padding: 10px 15px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box; /* Include padding and border in the element's total width and height */
font-size: 1rem;
}
button {
display: block;
width: 100%;
padding: 12px 20px;
background-color: #004a99;
color: white;
border: none;
border-radius: 4px;
font-size: 1.1rem;
cursor: pointer;
transition: background-color 0.3s ease;
margin-top: 10px;
}
button:hover {
background-color: #003366;
}
#result {
margin-top: 30px;
padding: 20px;
background-color: #e7f3ff;
border-left: 5px solid #004a99;
border-radius: 4px;
text-align: center;
font-size: 1.3rem;
font-weight: bold;
color: #004a99;
}
#result span {
color: #28a745; /* Success green for the calculated value */
}
.explanation {
margin-top: 40px;
padding: 25px;
background-color: #eef7ff;
border: 1px solid #cfe2ff;
border-radius: 8px;
}
.explanation h2 {
color: #004a99;
text-align: left;
margin-bottom: 15px;
}
.explanation p, .explanation ul li {
margin-bottom: 15px;
color: #555;
}
.explanation strong {
color: #004a99;
}
@media (max-width: 600px) {
.input-group {
flex-direction: column;
align-items: stretch;
}
.input-group label,
.input-group input[type="number"],
.input-group select {
flex-basis: auto; /* Reset basis for column layout */
width: 100%;
box-sizing: border-box;
}
.loan-calc-container {
padding: 20px;
}
h1 {
font-size: 1.8rem;
}
}
Ratio and Proportion Calculator
Understanding Ratios and Proportions
Ratios and proportions are fundamental mathematical concepts used to compare quantities and establish relationships between them.
A ratio is a comparison of two quantities by division. It tells us how much of one thing there is compared to another. Ratios can be expressed in several ways:
- Using a colon (e.g., 3:5)
- Using the word "to" (e.g., 3 to 5)
- As a fraction (e.g., 3/5)
In this calculator, the first ratio is represented by
Value A in Ratio 1 and
Value B in Ratio 1.
A proportion is an equation stating that two ratios are equal. It's essentially a statement of equality between two comparisons. For example, if the ratio of boys to girls in one classroom is 3:5, and the ratio of boys to girls in another classroom is 6:10, these two ratios form a proportion because they represent the same relative relationship.
Mathematically, a proportion can be written as:
a/b = c/d
Where 'a', 'b', 'c', and 'd' are numbers. 'a' and 'd' are called the extremes, and 'b' and 'c' are called the means.
This calculator helps you find an unknown value in a proportion when three of the four values are known.
How the Calculator Works:
Given two ratios, a:b and c:d, a proportion states that a/b = c/d.
If one value is unknown, we can rearrange the formula to solve for it:
- If 'a' is unknown: a = (b * c) / d
- If 'b' is unknown: b = (a * d) / c
- If 'c' is unknown: c = (a * b) / d
- If 'd' is unknown: d = (b * c) / a
This calculator specifically solves for 'd' (Value B in Ratio 2) if it's left blank or zero, using the formula:
Unknown Value B in Ratio 2 = (Value B in Ratio 1 * Value A in Ratio 2) / Value A in Ratio 1
Or, more generally, if you provide the unknown value for 'a', 'c', or 'b', it will calculate that instead.
Use Cases:
Ratio and proportion calculations are used extensively in various fields:
- Cooking and Baking: Scaling recipes up or down. If a recipe for 12 cookies requires 2 cups of flour, how much flour is needed for 30 cookies?
- Maps and Scale Models: Determining real-world distances from map scales or model dimensions.
- Mixtures and Dilutions: Calculating the correct proportions of ingredients in chemical solutions or industrial processes.
- Unit Conversions: Converting between different units of measurement (e.g., miles to kilometers, ounces to grams).
- Finance: Calculating stock splits, dividend ratios, or loan-to-value ratios (though this calculator is not specifically for financial products).
- Chemistry: Stoichiometry and solution concentrations.
Example:
Suppose you know that for every 3 apples, you have 5 oranges (Ratio 1: 3 apples, 5 oranges).
You also know you have 6 apples (Value A in Ratio 2 = 6). How many oranges do you have (Value B in Ratio 2 = ?)?
Using the calculator:
- Value A in Ratio 1: 3
- Value B in Ratio 1: 5
- Value A in Ratio 2: 6
- Value B in Ratio 2: (leave blank or 0)
The calculator will determine that you have 10 oranges. The proportion is 3/5 = 6/10.
function calculateProportion() {
var val1a = parseFloat(document.getElementById("value1_a").value);
var val1b = parseFloat(document.getElementById("value1_b").value);
var val2a = parseFloat(document.getElementById("value2_a").value);
var val2b = parseFloat(document.getElementById("value2_b").value);
var resultDiv = document.getElementById("result");
var result = "";
// Input validation
if (isNaN(val1a) || isNaN(val1b) || isNaN(val2a) || isNaN(val2b) ||
val1a === 0 || val1b === 0 || val2a === 0) {
// Check if only value2_b is missing (or zero) and other inputs are valid
if (!isNaN(val1a) && !isNaN(val1b) && !isNaN(val2a) && val1a !== 0 && val1b !== 0 && val2a !== 0 &&
(isNaN(val2b) || val2b === 0)) {
// Solve for val2b
var calculated_val2b = (val1b * val2a) / val1a;
if (!isNaN(calculated_val2b)) {
result = "The proportion is
" + val1a + ":" + val1b + " = " + val2a + ":" + calculated_val2b.toFixed(4) + "";
} else {
result = "Calculation error. Please check your inputs.";
}
} else {
result = "Please enter valid non-zero numbers for the known values.";
}
} else {
// If all four values are provided, check if they form a valid proportion
var ratio1 = val1a / val1b;
var ratio2 = val2a / val2b;
// Allow for small floating point inaccuracies
if (Math.abs(ratio1 – ratio2) < 0.00001) {
result = "The provided ratios form a valid proportion:
" + val1a + ":" + val1b + " = " + val2a + ":" + val2b + "";
} else {
result = "The provided ratios do
not form a valid proportion (
" + val1a + ":" + val1b + " vs
" + val2a + ":" + val2b + ").";
}
}
resultDiv.innerHTML = result;
}