## College Algebra (10th Edition)

$127.3\ \mathrm{ ft}$
The diagonal of the square is the hypotenuse of a right triangle whose legs are sides of the square. Apply the Pythagorean theorem. \begin{aligned}90^{2}+90^{2}&=d^{2}\\2\cdot 90^{2}&=d^{2}\\\\d&=\sqrt{2\cdot 90^{2}}\\d&=90\sqrt{2}\\d&\approx 127.3\ \mathrm{ft}\end{aligned}