This multiple-answer question reviews several Circle Theorems simultaneously.
Review each theorem carefully; eliminate any invalid statements.
Key Circle Theorems include: the angle at the center is twice the angle at the circumference; the angle in a semicircle is 90°; opposite angles of a cyclic quadrilateral add to 180°. Understanding these theorems allows students to solve problems with arcs, chords, and tangents, reason about angles, and perform calculations in GCSE geometry. Practising multiple theorems together improves speed, accuracy, and confidence when tackling diagrams with multiple properties.