The radius of earth is about 3960 miles. the radius of the moon is about 1080 miles. a. find the surface area of earth and the moon. round your answer to the nearest tenth of a million. the surface area of the earth is about million square miles and the surface area of the moon is about million square miles. b. compare the surface areas of earth and the moon. round your answer to the nearest tenth. the surface area of the earth is about times greater than the surface area of the moon. c. about 70% of the surface of earth is water. how many square miles of water are on earth’s surface? round your answer to the nearest tenth of a million. there are about million square miles of water on the earth's surface.