A dime is 1.8 cm in diameter. Earth's Moon is 3.844 × 1010 cm from Earth and has a diameter of 3.76 × 108 cm. At what distance from your eye would you have to hold a dime so that it has the same angular diameter as the full Moon
A)200 cm
B)2 cm
C)0.2 cm
D)2 AU
E)2 LY

Question

Quizplus · Accepted Answer

To have the same angular diameter, the ratio of the diameter to the distance must be the same for both the dime and the Moon. For the Moon, this ratio is (3.76 × 10^8 cm) / (3.844 × 10^10 cm). For the dime, this ratio is (1.8 cm) / x. Solving for x gives x = 200 cm.

A Dime Is 1