Answer
10
Work Step by Step
$\frac{2}{5}$ =$\frac{x}{25}$
5$\times$ x = 2$\times$25 set cross products equal
5x = 50 multiply
$\frac{5x}{5}$=$\frac{50}{5}$
x=10
Check
$\frac{2}{5}$ =$\frac{x}{25}$
$\frac{2}{5}$ =$\frac{10}{25}$
$\frac{2}{5}$ =$\frac{2}{5}$ True
10 is the solution