body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f8f9fa;
color: #333;
margin: 0;
padding: 20px;
display: flex;
justify-content: center;
align-items: flex-start;
min-height: 100vh;
}
.loan-calc-container {
background-color: #ffffff;
padding: 30px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
width: 100%;
max-width: 600px;
box-sizing: border-box;
}
h1, h2 {
color: #004a99;
text-align: center;
margin-bottom: 20px;
}
.input-group {
margin-bottom: 20px;
display: flex;
flex-direction: column;
align-items: flex-start;
}
.input-group label {
font-weight: bold;
margin-bottom: 8px;
color: #004a99;
}
.input-group input[type="number"],
.input-group select {
width: 100%;
padding: 10px 12px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box;
font-size: 1rem;
}
.input-group select {
cursor: pointer;
}
button {
width: 100%;
padding: 12px 15px;
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: #e9ecef;
border-radius: 4px;
text-align: center;
border-left: 5px solid #28a745;
}
#result h3 {
margin: 0 0 10px 0;
color: #004a99;
font-size: 1.3rem;
}
#result-value {
font-size: 2.5rem;
font-weight: bold;
color: #28a745;
}
.article-content {
margin-top: 40px;
padding: 25px;
background-color: #ffffff;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}
.article-content h2 {
color: #004a99;
border-bottom: 2px solid #004a99;
padding-bottom: 10px;
}
.article-content p {
line-height: 1.6;
margin-bottom: 15px;
text-align: justify;
}
.formula {
background-color: #eef2f7;
padding: 15px;
border-radius: 5px;
margin: 15px 0;
font-family: 'Courier New', Courier, monospace;
font-size: 0.95rem;
overflow-x: auto;
}
@media (max-width: 600px) {
.loan-calc-container {
padding: 20px;
}
#result-value {
font-size: 2rem;
}
}
Understanding Projector Throw Distance and Ratios
When setting up a home theater or presentation room, one of the most critical factors is projector placement. This placement is determined by the projector's "throw ratio" and the desired screen size. The throw distance is the distance between the projector lens and the screen. Getting this right ensures you achieve the intended image size without distortion or the need for excessive digital keystone correction, which can degrade image quality.
What is Throw Ratio?
The throw ratio is a specification provided by projector manufacturers that indicates the relationship between the distance the projector needs to be from the screen (the throw distance) and the width of the projected image. It's typically expressed as a range (e.g., 1.15-1.50:1) or a single number (e.g., 1.2:1). The formula for throw ratio is:
Throw Ratio = Throw Distance / Image Width
A lower throw ratio (e.g., 0.7:1) indicates a "short-throw" projector, which can create a large image from a short distance. A higher throw ratio (e.g., 2.0:1) indicates a "long-throw" projector, requiring more distance for the same image size.
Calculating Throw Distance
To determine the correct throw distance, you need to know your screen's diagonal size, its aspect ratio, and your projector's throw ratio.
First, we need to calculate the image width from the diagonal size and aspect ratio. The relationship between diagonal (D), width (W), and height (H) of a screen is governed by the Pythagorean theorem ($D^2 = W^2 + H^2$) and the aspect ratio ($AR = W/H$).
From $AR = W/H$, we get $H = W/AR$. Substituting this into the Pythagorean theorem:
$D^2 = W^2 + (W/AR)^2$
$D^2 = W^2 (1 + 1/AR^2)$
$W^2 = D^2 / (1 + 1/AR^2)$
$W = D / \sqrt{(1 + 1/AR^2)}$
Note: Screen sizes are typically measured in inches, but for practical throw distance calculations, we often convert to feet. 1 inch = 1/12 feet.
Once we have the image width in feet ($W_{ft}$), we can rearrange the throw ratio formula to solve for the throw distance:
Throw Distance = Throw Ratio * Image Width
This calculator simplifies these calculations for you.
Common Use Cases
- Home Theater Setup: Ensuring the projector is placed at the optimal distance for your screen size and room dimensions.
- Conference Rooms & Classrooms: Projecting clear, appropriately sized images without obstruction.
- Gaming Setups: Achieving immersive, large-screen experiences.
- Portable Projector Use: Quickly determining placement for temporary setups.
Always consult your projector's manual for its specific throw ratio range and optimal operating conditions.
function calculateThrowDistance() {
var screenSizeInches = parseFloat(document.getElementById("screenSize").value);
var aspectRatio = parseFloat(document.getElementById("aspectRatio").value);
var throwRatio = parseFloat(document.getElementById("throwRatio").value);
if (isNaN(screenSizeInches) || isNaN(aspectRatio) || isNaN(throwRatio) || screenSizeInches <= 0 || throwRatio <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Convert screen diagonal from inches to feet
var screenSizeFeet = screenSizeInches / 12.0;
// Calculate image width in feet using aspect ratio and diagonal in feet
// Formula: Width = Diagonal / sqrt(1 + (1/AspectRatio)^2)
var imageWidthFeet = screenSizeFeet / Math.sqrt(1 + Math.pow(1 / aspectRatio, 2));
// Calculate throw distance in feet
// Formula: Throw Distance = Throw Ratio * Image Width
var throwDistanceFeet = throwRatio * imageWidthFeet;
document.getElementById("result-value").innerText = throwDistanceFeet.toFixed(2);
document.getElementById("result").style.display = "block";
}