# Prove that the length of any parallel of latitude is equal to the length of the equator times the cosine of the latitude angle.

mathsworkmusic | Certified Educator

calendarEducator since 2012

starTop subjects are Math, Science, and Business

Assume as an approximation that the earth is a perfect sphere.

Call the radius of the sphere r.

Using the formula for the circumference of a circle, the length of the equator is 2pir

Now, draw a triangle with a point at the centre of the earth A, a point on a particular latitude line B and a point horizontally across from that directly above the...

(The entire section contains 191 words.)