What is the volume of a sphere to the nearest cubic foot?

Step 1: You need the radius to solve the problem, but only the diameter, which is 6 feet, is given. The radius is one-half the diameter: \( 6 \div 2 = 3\;{\rm{ft}}\). Use 3 feet for the radius. 

Step 2: Use the formula:    \(\begin{array}{c}V = {\textstyle{4 \over 3}}\pi {r^3}\\ \approx {\textstyle{4 \over 3}}\,\,\cdot \,\,3.14\,\,\cdot \,\,{3^3}\\ \approx \,\,{\textstyle{4 \over 3}}\,\,\cdot \,\,3.14\,\,\cdot \,\,27\,\\ \approx 113.04\;\text{cu ft}\end{array}\)

Step 3: Round to the nearest cubic foot.

                                        113.04 rounds to 113 cubic feet