Moon phases The phases of the moon can be described using the phase angle θ, determined by...

Moon phases The phases of the moon can be described using the phase angle θ, determined by the sun, the moon, and Earth, as shown in the figure. Because the moon orbits

Earth, θ changes during the course of a month. The area of the region A of the moon, which appears illuminated to an observer on Earth, is given by , where R = 1080 mi is the radius of the moon. Approximate A for the following positions of the moon:

(a) θ = 0°(full moon)

(b) θ = 180° (new moon)

(c) θ = 90° (first quarter)

(d) θ = 103°

EXERCISE