Hi, here is a geometry 'proof question'
Why, in an equilateral pentagon, can there be not more than two right angles?
Thanks for any guidance
Let A, B, C, D, E denote the vertices of the pentagon.
1. If you use 3 right angles at the vertices A, B, C you would get a square but not a pentagon.
2. Therefore the right angles must be at A, B and D. To be an equilateral pentagon the triangle CDE must be an equilateral triangle too. But there doesn't exist an equilateral right triangle.