01 · PARALLELOGRAM THEOREMS
Core Parallelogram Properties
PARALLELOGRAM THEOREMS
Key Geometric Properties
1. Theorem 8.1: A diagonal of a parallelogram divides it into two congruent triangles (△ABC ≅ △CDA).
2. Theorem 8.2: In a parallelogram, opposite sides are equal (AB = CD, AD = BC).
3. Theorem 8.4: In a parallelogram, opposite angles are equal (∠A = ∠C, ∠B = ∠D).
4. Theorem 8.6: The diagonals of a parallelogram bisect each other (AO = OC, BO = OD).