You're building a rectangular frame 10 inches by 11 inches. How many feet of wood do you need?

The problem above is simply asking for the perimeter of the frame. Perimeter is the sum of all side lengths of a shape. For this we have a rectangular shape therefore perimeter is calculated as:

P = 2l + 2w = 2 (11) + 2 (10) = 42 inches

P = 42 inches (1 ft / 12 inches) = 3.5 feet of wood is needed for the frame