Asked by: Maria&Bojidar

Since we're estimating, use 4000 miles for the Earth's radius, and calculate the area of its surface with the formula for the area of a sphere: 4 x x (radius)

4000 miles x 5280 ft/mile x 12 inches/ft is about 250 million inches for the Earth's radius, so the formula give:

4 x 3.14 x (250,000,000)

Answered by: Paul Walorski, B.A. Physics, Part-time Physics Instructor