Answer
$a = 2$ ft
$b = 6$ ft
Work Step by Step
1. Solve for $a$
$\frac{a}{6} = \frac{3}{9}$
$a = \frac{3 \times 6}{9}$
$a = \frac{18}{9}$
$a = 2$ ft
2. Solve for $b$
$\frac{b}{2} = \frac{9}{3}$
$b = \frac{9 \times 2}{3}$
$b = \frac{18}{3}$
$b = 6$ ft