Many a mathematician has received a long letter from an unknown sender who claims to have found a way to trisect an angle using only a straightedge and compass. The mathematician may read passages of ...

A full turn around a point equals 360º. If a full turn equals 360º, then the sum of the angles around a point must also be 360º. When you calculate angles around a point, you can use this fact to find ...

Parallel lines are lines that never cross each other - they keep the same distance apart from each other. When two lines intersect, the opposite (X) angles are equal. On parallel lines, alternate (Z) ...