How to prove that a+b+c+d+e = 540°?
Can anybody help? Thanks

2. ## Re: About polygons problem

Originally Posted by william24
How to prove that a+b+c+d+e = 540°?
Can anybody help? Thanks
1. The sum of the interior angles of a polygon with n vertices (n> 2) is calculated by:

$p+q+r+s+t = (n-2) \cdot 180^\circ$

Therefore the sum of all interior angles of a pentagon is 540°.

2. Now make a table:

a = 360° - p
b = 180° - q
...
e = 180° - t

Now calculate a + b + ... + e using the fact that you know p + q + ... + t already.

By the way: You constantly post your question in the wrong forum. Why?

You have posted a lot of questions but never have shown any form of own work. Why?