4-8Example 3

What is the volume of the triangular prism?

1. Use the Pythagorean Theorem to find the leg of the base of the prism. This leg is the height of the triangular base.

a2 + b2 = c2 Use the formula.

162 + b2 = 202 Substitute themeasure of each

side.

256 + b2 = 400 Simplify theexponents.

4-8Example 3

What is the volume of the triangular prism?

b = 12 Simplify the squareroots.

The length of the leg is 12 inches.

Take the square root

of both sides.

b2 = 144 Subtract.

2. Next find the area of the base.

4-8Example 3

What is the volume of the triangular prism?

Use the area of a triangleformula to find the area of

thebase.Substitute the base and

heightof the triangle.Multiply.

The area of the base is 96 inches.

4-8Example 3

What is the volume of the triangular prism?

3. Then find the volume of the prism.

V = B × h Use the formula for the volume of a

triangular prism.

V 96 × 3 Substitute the area of the circle and

the height of the prism.

V 288 Multiply.

The volume of the triangular prism is about 288 cubic inches.