Question

A sphere has a radius of 5.3 feet.

Answer 1

V = (4/3)π*r^3
.. = (4/3)*3.14*(5.3 ft)^3
.. = 623.3 ft^3

Answer 2

Remember the equation for the volume of a sphere is: $V = \frac{4}{3} \pi r^{3}$
where V=volume and r =radius 

Since you know the radius is 5.3 ft, plug that into the equation for volume of a sphere:
$V = \frac{4}{3} \pi r^{3}\\ V = \frac{4}{3} (3.14) (5.3)^{3}\\ V= 623.3 ft^{3}$

The volume of the sphere is: 623.3 $ft^{3}$