- 1. Angles on a Straight Line, at a Point, and Vertically Opposite Angles
Apply the 180° straight-line rule and the 360° angles-at-a-point rule, prove that vertically opposite angles are equal, and evaluate true/false statements about intersecting lines.
- 2. Parallel Lines Cut by a Transversal
Identify corresponding, alternate, and co-interior angle pairs, state and prove each property, and solve algebraic problems from parallel-line diagrams.
- 3. The Angle Sum of a Triangle and the Exterior Angle Theorem
Prove that a triangle's angles sum to 180° using parallel-line rules, prove and apply the exterior angle theorem, and solve multi-step triangle problems.
- 4. Congruent Triangles: Conditions and Application
State and apply the five congruence conditions (SSS, SAS, ASA, AAS, RHS), explain why AAA fails, write correct vertex correspondence, and use congruence to deduce equal parts.
- 5. Properties of the Parallelogram and the Intercept Theorem
Prove and apply the four parallelogram properties, compute its area with perpendicular height, and use the intercept theorem to find unknown lengths from proportional intercepts.
