Our big idea today: a parallelogram is a quadrilateral with opposite sides congruent, and parallelograms have four additional properties (which we are proving with a 2-column proof or by discussion verbally).

Students checked their previous night's homework. A grade was taken on HW #14 & #15 for those who had not done so yet (A day and part of 6th period). A day students get their last test back to view grade and mistakes.

Attached is a copy of the fill-in-the-blank proof for "Opposite sides of a parallelogram are congruent. Opposite angles of a parallelogram are congruent."

There are also sketches and an argument for:

Parallelogram diagonals bisect each other.

Consecutive angles in a parallelogram are supplementary.

For homework #16, (16B on B day): pp 281-3: 1-6, 11, 16-18. AND write up C-42-45 with sketches from board or handouts (the conjectures begin on p 279).

parallelogram_definition_properties_and_hw_answers.pdf |