EXAMPLE 4 Find the volume of a sphere

SOLUTION

The soccer ball has a diameter of 9 inches. Find its volume.

Formula for volume of a sphere

Substitute.

V = πr343

= π(4.5)343

The diameter of the ball is 9 inches, so the radius is

= 4.5 inches.

92

EXAMPLE 4 Find the volume of a sphere

= 121.5π

≈ 381.70

Simplify.

Use a calculator.

The volume of the soccer ball is 121.5π, or about 381.70 cubic inches.

ANSWER

EXAMPLE 5 Find the volume of a composite solid

SOLUTION

= πr2h – ( πr3)12

43

= π(2)2(2) – π(2)323

Substitute.

Formulas for volume

23

= 8π – (8π) Multiply.

Find the volume of the composite solid.

EXAMPLE 5 Find the volume of a composite solid

= π – π243

163

83= π

Rewrite fractions using leastcommon denominator.

Simplify.

The volume of the solid is π, or about 8.38 cubic inches.

83

ANSWER

GUIDED PRACTICE for Examples 4 and 5

4. The radius of a sphere is 5 yards. Find the volumeof the sphere. Round your answer to two decimal places.

The volume of the sphere is 523.81yd2

ANSWER

GUIDED PRACTICE for Examples 4 and 5

5. A solid consists of a hemisphere of radius 1 meter on top of a cone with the same radius and height 5 meters. Find the volume of the solid. Round your answer to two decimal places.

The volume of the solid is 7.33m2

ANSWER