## Precalculus (6th Edition) Blitzer

$63.7\ ft$.
Using the figure as shown in triangle ABC, we have the angle $B=45^\circ$. Using the Law of Cosines, we have $b^2=90^2+60.5^2-2(90)(60.5)cos(45^\circ)\approx4060$ which gives $b\approx63.7\ ft$.