Hasan is painting a spherical model of a human cell for his science class. He uses 100π square inches of paint (in one coat) to evenly cover the outside of the cell. What is the diameter of Hasan’s cell model?

The surface area of a sphere is 4πr². Setting it equal to 100π gives 4πr² = 100π, so r² = 25 and the radius is 5 inches; the diameter is twice the radius, or 10 inches. The correct choice is C, 10.0 in.

AI-written and checked against the verified answer.