Understanding Ratios & Proportions
A ratio is simply a way to compare two quantities. When we say a recipe calls for a 2:1 ratio of flour to sugar, it means that for every 2 cups of flour, you need 1 cup of sugar. Ratios are essentially fractions written side-by-side!
1. How to Simplify a Ratio
Simplifying a ratio works exactly like simplifying a fraction. You find the Greatest Common Divisor (GCD)—the largest number that divides evenly into both sides—and divide.
Both numbers can be divided by 5.
15 ÷ 5 = 3
20 ÷ 5 = 4
Simplified Ratio: 3 : 4
2. Solving Equivalent Ratios (Solving for X)
If you have two ratios that are equal, they form a proportion (like A:B = C:D). If one of these numbers is missing, you can find it using cross-multiplication.
Example: 2 : 5 = 6 : X
Step 1: Multiply B and C (5 × 6 = 30)
Step 2: Divide by A (30 ÷ 2 = 15)
Answer: X = 15
Real-World Use Case: Aspect Ratios
If you are a web developer or graphic designer, you use ratios constantly. A standard HD television has an aspect ratio of 16:9. If you want to design a smaller graphic that fits this exact screen shape perfectly and you know you want it to be 800 pixels wide, you would use our "Scale" tool. It will calculate that your height must be exactly 450 pixels!