A rain gutter is made from sheets of aluminum that are 20 inches wide. As shown in the fig...

A rain gutter is made from sheets of aluminum that are 20 inches wide. As shown in the figure, the edges are turned up to form right angles. Determine the depth of the gutter that will allow a cross−sectional area of 13 square inches. Show that there are two different solutions to the problem. Round to the nearest tenth of an inch.