## Intermediate Algebra for College Students (7th Edition)

$8.94$ (approximately)
Apply Pythagorean theorem. $c^2=a^2+b^2$ Plug $a=4 ft$ and $b= 8 ft$. We have $c^2=16+64$ or, $c^2=80$ or, $c=\sqrt {80}$ or, $c=4\sqrt 5$ or $c=8.94$ (approximately)