Imagine you and your colleague are astronauts who have landed on the moon of a planet in another galaxy. One of your many tasks is to determine the circumference of the moon. You remember learning about how Eratosthenes calculated the circumference of the Earth using shadows and geometry, and you decide to use this technique on the alien moon. You set two poles upright on the surface of the moon that are spaced 1,000 km apart. One person stands at each pole and, at precisely noon, you each measure the angle of the shadow made by the pole. At one pole the shadow makes a 22.5 degree shadow, and at the other pole there is no shadow because the star of this system is directly overhead. What is the circumference of this alien moon? a. 16,000 km.
b. 40,008 km.
c. 50,000 km.
d. 11,500 km.