Lesson Plan

Prove that opposite sides of a parallelogram are congruent, using triangle congruence and the properties of parallel lines

Prove that opposite angles of a parallelogram are congruent, using the properties of parallel lines and supplementary co-interior angles

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

Prove that rectangles are parallelograms with congruent diagonals, and conversely, that a parallelogram with congruent diagonals is a rectangle

Distinguish between properties of general parallelograms and properties specific to special parallelograms (rectangles, rhombi, squares) and apply these theorems in multi-step proofs

HSG.CO.C.11

HSG.CO.C.11: Prove theorems about parallelograms. Theorems include: opposite sides are congruent, opposite angles are congruent, the diagonals of a parallelogram bisect each other, and conversely, rectangles are parallelograms with congruent diagonals.