Answer
b=$\sqrt 72$
b$\approx8.485yds$
Work Step by Step
$a^{2}$ +$b^{2}$ =$c^{2}$ Let a=3yd. and c=9yd.
$3^{2}$ +$b^{2}$ =$9^{2}$
9+$b^{2}$=81
$b^{2}$=81-9
$b^{2}$ =72
b=$\sqrt 72$
b$\approx8.485yds$
The length of the leg is exactly $\sqrt 72$ and approximately 8.485 yds
