Question

The mean radius of earth is 6,371.0 kilometers and the mean radius of Earth's Moon is 1,737.5 kilometers.What is the approximate difference in the mean circumference,in kilometers, of earth and Earth's moon? Round your answer to the nearest tenth of a kilometer.

Answer 1

We calculate for the circumferences of Earth and moon by using the equation,

C = 2πr

For Earth,

C = 2π(6371 km) = 40030.2 km

For Moon,

C = 2π(1737.5 km) = 10917.0 km

The difference between the two circumferences is 29113.2 km approximately.

Answer 2

d≈2π(6371-1737.5)

d≈9267π

d≈29113.1km (to nearest tenth of a kilometer)