Theorems

All articles filed under Theorems.

Circle Theorems Made Simple: Angle in a Semicircle and Cyclic Quadrilaterals
- September 28, 2026

Circle Theorems Made Simple: Angle in a Semicircle and Cyclic Quadrilaterals

How the angle in a semicircle and cyclic quadrilateral theorems work, why they are true, and how to apply both in GCSE-style questions.