# Proportion Formula

An equation is said to be in proportion when the elements in it, say, a, b, c and d are in proportion. A and d are called extremes and b and c are called mean terms. The product of mean in the ratio are equal to product of extremes. Two ratio are either equal if their cross products are equal.

The **Proportion Formula** is given as,

\[\large a:b::c:d\Rightarrow \frac{a}{b}=\frac{c}{d}\]

### Solved Examples

**Question 1: **What is the value of x in 6: x :: 2 : 5?

**Solution:**

6:x :: 2:5

6:x = 2:5

$\frac{6}{x}$ = $\frac{2}{5}$

6 $\times$ $\frac{5}{2}$ = x

x = 6 $\times$ $\frac{5}{2}$

x = $\frac{30}{2}$

x = 15

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Percent Composition Formula | Sine Cosine Tangent Formula |

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