A ladder is needed to reach the top of a second floor window, A distance of 20 feet above the (level) ground. According to the directions on the ladder, the distance between the bottom of a leaning ladder and the base of the (vertical) wall it is leaning up against should be 30% of the length of the ladder. Find the length of the ladder that will just to reach the top of the second-floor window when positioned as the directions describe.

1 answer

If the ladder has length z, then

(.3z)^2+20^2 = z^2
z ≈ 21 ft