Volume is the number of cubic units required to completely fill a 3-dimensional object. The units of volume are called cubic units because they are little cubes that are one unit long, one unit wide, and one unit high. These units are specific units in a measurement system.

Answer the following questions. Click the blanks to reveal the answers.

• If an object is measured in inches, then the volume is measured in __________. cubic inches.
• If the metric system is used, the units might be centimeters or meters. The area is then measured in _____ cubic centimeters or _____ cubic meters.

Determine an appropriate measure for the volume of the everyday items listed below.

Tennis ball: __________ cubic inch

A basketball: __________ cubic foot

The volume of a sphere is measured in cubic units. The formula to find the volume is: V = 4 3 r³

Example: A sphere has a diameter of 12 feet. Determine the volume of the sphere.

Answer the following questions. Click the blanks to reveal the answers.

• The radius of the sphere is _______________. 12 feet ÷ 2 = 6 feet.
• The volume of the sphere is _______________________________________. V = 4 3 π(6 ft)³ = 4 3 π(216 ft³) = 288π ft³ ≈ 904.32 ft³.

Comparing the Surface Area and Volume of a Sphere

Real World Problem

The circumference of a regulation NBA basketball is 29.5 inches. Determine the volume of air required to inflate 4 basketballs before a game starts.

Answer the following questions. Click the blanks to reveal the answers.

• The problem is asking us to find the ______ volume of the basketball.
• The basketball is a sphere and the formula for volume of a sphere is _______. V = 4 3 πr³.
• In order to find the volume the ______ radius of the basketball is needed.
• The _____________ circumference formula is used to find the radius of the sphere.
• The formula for circumference is _______. C = 2πr.
• The circumference of the basketball is ____. 29.5.
• Substitute the circumference of the basketball into the circumference formula: ________. 29.5 = 2πr.
• Solve for r: _______________. 29.5 2π = r   r ≈ 4.7 inches.
• Substitute the radius into the formula for the volume to find the volume of the basketball: _________________________________________. V = 4 3 πr³ = 4 3 π(4.7 in.)³ = 4 3 π(103.8 in.³) ≈ 434.7 in.³
• The volume for 4 NBA basketballs is _____________________. 434.7 in.³ * 4 = 4738.8 in.³