Prove theorems about parallelograms

What you'll learn

1. Prove that opposite sides of a parallelogram are congruent, using triangle congruence and the properties of parallel lines
2. Prove that opposite angles of a parallelogram are congruent, using the properties of parallel lines and supplementary co-interior angles
3. Prove that the diagonals of a parallelogram bisect each other, and conversely, that if the diagonals of a quadrilateral bisect each other, the quadrilateral is a parallelogram
4. Prove that rectangles are parallelograms with congruent diagonals, and conversely, that a parallelogram with congruent diagonals is a rectangle
5. Distinguish between properties of general parallelograms and properties specific to special parallelograms (rectangles, rhombi, squares) and apply these theorems in multi-step proofs

Prerequisites

• Prove theorems about lines
• Prove theorems about triangles