The diameter of a sphere placed inside a cylinder is equal to the height and to the diameter of the cylinder. If the diameter of the cylinder is 8 centimeters, what is the surface area of the sphere?
+591 The surface area of a sphere is 4$\pi$r$^2$, and the diameter is 8, so the radius is 4, so we plug in 4 for r, and we get:
$4\pi\cdot16=\boxed{64\pi}$
