# Surface area of house

This is the image:

So the question is:

(a) Ralph is painting the barn, including the sides and roof. He wants to know how much paint to purchase. What is the total surface area that he is going to be painting? Round to the nearest hundredth.

(b) If one paint can covers 57 square feet, how many paint cans should he purchase?

(c) If each paint can costs $\$23.50$, how much will the paint cost? I've done a little the first part, but since the surface area is off, all the other parts are off as well. Please show me how to get the surface area My work so far (A) Total Surface Area Rectangular Prism 2(wl + hl + hw) 2 (45 x 20 + 15 x 20 + 15 x 45) = 3750 Triangular Prism L + 2B h(a + b + c) + Ab 45(15 + 20 + 15) + 4 x 20 2250 + 80 2330 Total surface area - 3750 + 2330 6080 (B) Paint Cans 6080 / 57 106.6 or 107 paint cans I had to divide the total surface area with how much area one paint can would cover. (C) Price If each paint can costs$\$23.50$, and Ralph buys 107 paint cans, he will spend $\$2,514.50\$

• You're including the area of the floor and the (twice) the area of the face between the two shapes. Aug 10 '16 at 6:41
• In other words, this is not a rectangular prism. Aug 10 '16 at 7:18
• Aug 11 '16 at 1:48