The radius of this ball is 15 inches. Which equation gives the ball's surface area, in square inches?

Best to look up the formula for the surface area of a sphere and then find it:
A = 4πr^2, where r is the radius of the sphere. Then,
A = 4π(15 in)^2 = 4(3.14)(225 in^2) = 2826 in^2 (answer)
This is represented by the formula given in the lower left.