###### Exercise78

The diagonal length (\(D\)) of a rectangle with side lengths \(L\) and \(W\) is given by:

\(\displaystyle{ D=\sqrt{L^2+W^2} }\)

Determine the diagonal length of rectangles with \(L={9\ {\rm ft}}\) and \(W={12\ {\rm ft}}\text{.}\)

The diagonal length of rectangles with \(L={9\ {\rm ft}}\) and \(W={12\ {\rm ft}}\) is .