Khan Academy
Khan Academy: Geometry: Proof: Opposite Sides of Parallelogram Congruent
Demonstrates how to prove that the opposite sides of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [8:30]
Khan Academy
Khan Academy: Geometry: Proof: Opposite Angles of Parallelogram Congruent
This video tutorial demonstrates how to prove that the opposite angles of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal. [4:08]
Khan Academy
Khan Academy: Geometry: Proof: Diagonals of Parallelogram Bisect Each Other
Demonstrates how to prove that the diagonals of a parallelogram bisect each other based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [9:06]