Question

A simple impact crater on the moon has a diameter of 15 kilometers. A complex impact crater has

a radius of 30 kilometers. How much greater is the circumference of the complex impact crater than
the simple impact craters?

Answer 1

141.3 km

Explanation:

First crater has the radius (that is, half the diameter) of 7.5 km; the circumference of this crater is C = 2(pi)r, or 2(3.14)(7.5 km) = 47.1 km;

Second crater radius is C = 2(pi)(30 km) = 188.4 km

The circumference of the complex (larger) impact crater is

(188.4 - 47.1) km greater than the circumference of the simple (smaller) crater:

141.3 km