Mathematics

Proving that the Angles in a Triangle Sum up to 180°

Proving that the angles inside a triangle – any triangle – sum up to 180° is very simple, but leaves most people unsatisfied (or unconvinced) because it depends on the properties of something called Alternate Interior Angles. I’ll give the proof first and then explain Alternate Interior Angles A demonstration of the angles of a […]

Mathematics

Demonstrating that the Angles in a Triangle Sum up to 180 Degrees

We are taught that the sum of the angles in a triangle add up to 180° Here is a simple way to demonstrate that fact. A proof of the angles of a triangle summing to 180° can be found here. Materials paper pencil or pen ruler (or some sort of straight-edge) coloured crayon scissors 1) […]