The volume of the ball is:
[tex]V_{ball}=\dfrac{4}{3}\pi r^3.[/tex]
If the diameter of a tennis ball is 6.42 cm, then the radius of tennis ball is 3.21 cm. Then
[tex]V_{ball}=\dfrac{4}{3}\pi (3.21)^3=44.101548\pi=44.101548\cdot 3.14=138.47886072[/tex] sq. cm.
Answer: [tex]V_{ball}=138.47886072[/tex] sq. cm.
