Do you recall your high school geometry? Given isosceles triangle ABC, where side AB is equal to side BC, then angle A is also equal to angle C. That’s not something your math teacher invented—it’s a ...

The angle at the circumference in a semicircle is 90°. Angle STU = 90° Angles in a triangle add up to 180°. The angle on a straight line is 180°. The angle VOY = 180°. The angle at the centre is ...

👉 Learn how to write a proof given a triangle. A triangle is a polygon with three sides. A proof is a series of statements and reasons that establishes the truth of a mathematical claim (statement).

Revise the different types of angles and rules for calculating angles. This guide includes interactive activities and a quiz. NEW: Angles in parallel lines Revise alternate, correspondent or ...