Geometry and proof.
Connect angle, triangle and circle theorems in clear proofs and reliable construction methods.
Work through the topic
Learn the method, follow the examples, then try the worksheet.
- 01
Angle and similarity reasoning
Link angle facts with corresponding sides in similar figures.
- 02
Congruent/similar triangles in proofs
Choose sufficient congruence or similarity information and write a logical proof.
- 03
Chords, radii and tangents
Use perpendicular radii, chord symmetry and equal tangents in circle problems.
- 04
Angles at the centre and circumference
Connect angles at a circle’s centre and circumference using the same intercepted arc.
- 05
Circle theorems and their applications
Use cyclic quadrilateral and tangent–chord relationships with clear conditions.
- 06
Connected deductive arguments
Arrange given facts and deductions into a proof that establishes the stated conclusion.
- 07
Construction/spatial algorithms
Describe and justify geometric constructions as repeatable algorithms.
- 08
Testing and justifying solutions
Test geometric claims systematically and distinguish proof from a plausible diagram.
Topic review
Revisit the key ideas, then choose a practice paper.