In today's class we started chapter 6 which talks about quadrilaterals. We went over lesson 6-1 and one theorem of lesson 6-2 just to predict what we are going to work with tomorow. Lesson 6-1 talks about parallelograns, so we studied the definition of a parallelogram and other four theorems:
Theorem 6-1: if: it's a parallelogram
then: both pairs of opposite sides are congruent

Theorem 6-2: if: it's a parallelogram
then: both pairs of opposite angles are congruent

Theorem 6-3: if: it's a parallelogram
then: consecutive angles are supplementary

Theorem 6-4: if: it's a parellelogram
then: diagonals bisect each other
We also proved theorem 6-1 and 6-2 that was necessary to go back to postulates and theorems related to parallel lines and congruent angles that we have studied already. All the theorems of the lesson 6-1 it's when you know that is a parallelogram and with this given information you can conclude it's characteristcs.
In lesson 6-2 we saw theorem 6-5:
Theorem 6-5: if: a quadrilateral has both pairs of opposite sides
then: it's a parallelogram
In this theorem you know the characteristcs then you can conclude that is a parallelogram. So, the theorems of lesson 6-2 are the converse of the theorems of lesson 6-1. Finally we proved theorem 6-5 that was also necessary to use theorems and postulates related to parallel lines and congruent angles.
HW: pg 295 #17-35 all.