You plan to paint the outside of this barn, including the roof, but not the floor. Which calculation will help you best decide how much paint you will need?

a. Add the volumes of 1 rectangular prism and 1 triangular prism.


b. Add the areas of 9 rectangles and 2 triangles.


c. Add the perimeters of 4 rectangles and 2 triangles.


d. Add the areas of 6 rectangles and 2 triangles.