# ASVAB Mathematics Knowledge Practice: Surface Area

Just as there are different sides to every story, there are also different sides to every three-dimensional object. Some questions on the Mathematics Knowledge subtest on the ASVAB will ask you to add up all the sides of a figure to find its total surface area.

## Practice questions

- Find the surface area:
**A.**48 square yards

**B.**72 square yards

**C.**90 square yards

**D.**96 square yards - Find the surface area:
**A.**2,800 cm^{2}

**B.**2,820 cm^{2}

**C.**2,826 cm^{2}

**D.**2,152 cm^{2}

## Answers and explanations

- The correct answer is
**Choice (D).**The formula to find the surface area of a prism is

*SA*= 2*B*+*Ph*, where*B*represents the area of the base,*P*represents the perimeter of the base, and*h*represents the height of the prism.First find the area of the triangular base using

where

*b*represents the triangle’s base and*h*represents its height:Find its perimeter by adding the length of each leg:

6 + 8 + 10 = 24

The base’s area is 24 square yards, the base’s perimeter is 24 yards, and the prism’s height is 2 yards, so plug that information into the formula for the surface area of a prism:

*SA*= 2(24) + 24(2)*SA*= 48 + 48*SA*= 96The surface area of the prism is 96 square yards.

- The correct answer is
**Choice (C).**The formula to find the surface area of a sphere is

so use the values you know to solve the problem: