A pole of length L is carried horizontally around a corner where a 3-ft-wide hallway meets a

Question:

A pole of length L is carried horizontally around a corner where a 3-ft-wide hallway meets a 4-ft-wide hallway. For 0 < θ < π/2, find the relationship between L and u at the moment when the pole simultaneously touches both walls and the corner P. Estimate u when L = 10 ft.

Pole, length L 4 ft 3 ft