Sum+of+Angles+in+a+Quadrilateral

=Sum of Angles in a Quadrilateral=

[|Java Parallelogram Explorer] This is a link to a quick Java sketch of a parallelogram which can be used to help students determine that opposite angles in a parallelogram are congruent and that consecutive angles in a parallelogram are supplementary.

NCTM Illuminations Tesselations Lesson- extension that builds on the sum of the angles in a polygon.