A geometric proof. Prove two angles in this model are equal in measure.

A geometry proof involving exterior angles of a triangle.

A geometry proof problem involving a right triangle and finding angles of equal measure.

A "three star geometry problem" - requiring the knowledge of biconditional statements and how to prove such problems.

Discovering the properties of constructions, seeing proofs in action, and viewing problems come to life here with this wonderful use of technology in the classroom. Single steps are explained and illustrated one at a time so that the...

MathWorld provides the definition of a rectangle and the area formula of a rectangle.