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Home > GC > Chapter 11 > Lesson 11.2.1 > Problem 11-74


The moon is an average distance of miles away from the Earth. While that seems very far, how far is it?  

  1. Compare that distance with the circumference of the Earth’s equator. Assume that the Earth’s radius is miles. How many times greater than the Earth’s circumference is the distance to the moon?

    The formula to find the circumference of a circle is .

    times greater

  1. Dashed right triangle, titled, drawing not to scale, with vertical shorter leg, and horizontal longer leg. Circles around each vertex, labeled as follows: Right angle, moon, opposite vertical leg, sun, opposite horizontal leg, earth, and, A.One way to estimate the distance between the Earth and the sun is to consider the triangle formed by the sun, Earth, and moon when the moon appears to be half-full. (See the diagram at right.) When the moon appears from earth to be half-full, it can be assumed that the moon forms a angle with the sun and the Earth.

    Using special equipment, Ray found the measure of angle to be . If the moon is miles away from the Earth, then how far is the sun from the Earth?