Interior angles in a triangle add up to 180˚. Triangles close triangleA polygon with three straight sides. have three sides, therefore they have three angles. Interior angles in a triangle sum to a ...

Before reading this guide, it may be helpful to read the guides from Module 1 on the properties of angles and the properties of 2D shapes. The sum of the angles inside any polygon can be found by ...

We’ve all learned “parallel lines never intersect” in high school geometry. But what your teachers failed to explain is that “parallel lines never intersect” is only true in Euclidean geometry, which ...

Blaise Pascal independently rediscovered classical geometry at the age of 12 despite a ban on formal maths studies. His early ...