# Practice Math Questions for Praxis: Prisms

Prisms weren’t invented just to divide light into beautiful rainbows; they’re also useful for inducing painful headaches when you’re asked to find their surface area or volume on the Praxis Core exam.

Swallow a headache tablet and try the following practice questions. In the first one, you have to find the surface area of a right rectangular prism. In the second one, you’re asked to find the volume of a triangular prism.

## Practice questions

- The following figure is a right rectangular prism. What is its surface area?
**A.**266 m^{2 }**B.**144 m^{2 }**C.**246 m^{2}

**D.**432 m^{2}

**E.**348 m^{2} - A triangular prism has two triangular bases that both have an area of 19 square units. The prism has a height of 8 units. What is the volume of the prism?
**A.**604 cubic units

**B.**76 cubic units

**C.**27 cubic units

**D.**152 cubic units

**E.**228 cubic units

## Answers and explanations

- The correct answer is Choice
**(E).**The surface of any right prism is

*Ph*+ 2*B,*which is the product of the perimeter of a base and its corresponding height, plus twice the area of the base. Any face of a right rectangular prism can be considered a base, and what you use for height must be the measure of a segment perpendicular to the face you decided to consider a base. For example, if you consider an 8 m-by-9 m face a base for the right rectangular prism in this problem, you must consider 6 m to be the height. In that case, the other 8 m-by-9 m face is also a base.The surface area of the right rectangular prism is 348 m

^{2}. - The correct answer is Choice
**(D).**The volume of any prism is

*Bh*, or base area times the height:The volume of the prism is 152 cubic units.