On a photograph of Earth's moon, the Moon measures 30 cm in diameter and a small crater measures 0.2 cm. The Moon's physical diameter is 1738 km. What is the physical diameter of the small crater?

Question

Quizplus · Accepted Answer

The scale of the photograph can be found by dividing the physical diameter of the Moon by its diameter in the photograph: 1738 km / 30 cm = 57.93 km/cm. Multiplying the diameter of the crater in the photograph by this scale gives its physical size: 0.2 cm * 57.93 km/cm = 11.586 km, which is approximately 12 km.

On a Photograph of Earth's Moon, the Moon Measures 30