# Solid Angle Question

1. Jan 23, 2008

### AnthonyS

1. The problem statement, all variables and given/known data

How many inches from your face would you have to hold a dime in order for it to appear the exact same size as the Moon? Use a distance to the Moon of 384,400 km and a radius of the Moon of 1738 km. The diameter of a dime is 17.1 mm. (Hint: Find at what distance a dime has the same solid angle as the Moon).

2. Relevant equations

dω = sin θ dθ dφ

3. The attempt at a solution

This is for my Physics of Meteorology class. I am trying to find the solid angle of the moon as seen from Earth first, and then will attempt the rest. I have thus far, ω=$$\int\int$$sin θ dθ dφ, where the first integral goes from 0 to 2pi and the second from 0 to θ, but I'm lost as to how to solve it.

Anthony

2. Jan 24, 2008