# Proportion Formula

An equation where two ratios are said to be equivalent is known as proportion. Suppose p, q, r and s are said to be in proportion , then

**The proportion formula is,**

p : q :: r : s $\Rightarrow$ $\frac{p}{q}$ = $\frac{r}{s}$.

Where,

p & s are extremes,

q & r are mean terms.

If the cross products of the two ratios are equal then the ratios are equivalent.