Answer
Length of escalator $\approx 23.1$ feet
Work Step by Step
If escalator makes an angle of 60 degrees, then-
side opposite $60^{\circ}$ = 20 feet
Therefore
Shortest side = $\frac{Side opposite 60°}{\sqrt 3}$ = $\frac{20}{\sqrt 3}$
Shortest side = $\frac{20\times\sqrt 3}{ \sqrt 3\times\sqrt 3}$ = $\frac{20\sqrt 3 }{3} $
Longest Side = 2 $\times $ shortest side = 2$\times\frac{20\sqrt 3}{3}$
Longest Side = $\frac{40\sqrt 3 }{3} \approx 23.1$
Therefore length of escalator $\approx 23.1$ feet