A straight ladder is leaning against the wall of a house. The ladder has rails 4.80 meter long, joined by rungs 5.200 meter long. Its bottom end is on solid but sloping ground so that the top of the ladder is 3.800 meter to the left of where it should be, and the ladder is unsafe to climb. You want to put a rock under one foot of the ladder to compensate for the slope of the ground.
Find what should be the thickness of the flat rock?
cm