SWBAT prove key theorems relating to parallelograms, like opposite sides are congruent and opposite angles are congruent

Proofs + Parallelograms = Pretty Pairing! Students prove that opposite sides in a parallelogram are congruent and that opposite angles are also congruent.

10 minutes

This Do Now is a formative assessment of students' knowledge of finding the interior angle of a polygon. This is a great question to collect and grade, and also can be extending by asking students to write their steps to solving rather than telling a partner.

30 minutes

15 minutes

The activity/homework asks students to look for repeated reasoning to use coordinate geometry to find the 4th point in a parallelogram (MP8). Although the questions are scaffolded for students questions #1-7 and the proof #8 require students to work through and persevere through both challenging problems, just as they were required to in the proofs earlier in class (MP1).