Today was "Parallelogram Day" in Geometry. We observed the definition of parallelogram from sketches: a quadrilateral with opposite sides parallel. We proved that opposite angles of a parallelogram are congruent (C-45) and opposite sides of a parallelogram are congruent (C-47). We then used C-47 to argue that parallelogram diagonals bisect each other (share a midpoint). Of course consecutive angles between bases are supplementary (like we learned last fall) (C-46).

We then used common sense to figure out the midpoint formula for segments in the coordinate plane (which will also allow us to see if diagonals share a midpoint).

HW #16: p 281-3: 1-6,11, 15-17, p 37: 3-4, 6-8.

And write up C 45 to C 48 from pp 269-70 (using notes to help you get sketches and fill-in-the-blank.

Students made sure they understood the kite and trapezoid conjectures and found their mistakes on homework over that.

There will be a quiz on Thursday-Friday over sections 1-4 of Chapter 5. Midpoint will be on the quiz. The quiz will have some true/false over C-30,32-41, and 44. The rest of the quiz will be missing angles or sides found using what you know from the conjectures. One midpoint problem.

"Test" will be Thursday-Friday next week, with 1st and 2nd having a shorter test than 6th-8th.

We then used common sense to figure out the midpoint formula for segments in the coordinate plane (which will also allow us to see if diagonals share a midpoint).

HW #16: p 281-3: 1-6,11, 15-17, p 37: 3-4, 6-8.

And write up C 45 to C 48 from pp 269-70 (using notes to help you get sketches and fill-in-the-blank.

Students made sure they understood the kite and trapezoid conjectures and found their mistakes on homework over that.

There will be a quiz on Thursday-Friday over sections 1-4 of Chapter 5. Midpoint will be on the quiz. The quiz will have some true/false over C-30,32-41, and 44. The rest of the quiz will be missing angles or sides found using what you know from the conjectures. One midpoint problem.

"Test" will be Thursday-Friday next week, with 1st and 2nd having a shorter test than 6th-8th.