The shadow of a woman standing next to a tree is 3 feet long, and the shadow of the tree is 12 feet long. If the woman is 5 feet, 6 inches tall, how tall, in feet, is the tree?

Because the lengths of objects and their shadows are proportional, the easiest way to do this problem is to observe that the shadow of the tree is four times longer than the shadow of the woman, so the tree is four times taller than the woman. Four times 5 feet, 6 inches is 22 feet.