#### Answer

$a=30; b=60$

#### Work Step by Step

1. First we need to find the ratio by setting up two similar sides of the triangles. In this case, we know both hypotenuses, so we use them to set our ratio. It is better to reduce the ratio, if it is possible.
$\frac{75}{25}=\frac{3}{1}$
2. Make following three equivalent ratios
$\frac{3}{1} =\frac{a}{10} =\frac{b}{20}$
3. We will solve variable at a time, first find a
$\frac{3}{1} =\frac{a}{10}$
$a=30$
4. Then find the second side b
$\frac{3}{1} =\frac{b}{20}$
$b=60$