Discover more at www.ck12.org: [ Ссылка ]

Here you'll learn how to apply various quadrilateral theorems to prove that a quadrilateral is a parallelogram.

This video provides the student with a walkthrough on proving that a quadrilateral is a parallelogram.

This is part of CK-12’s Basic Geometry: Polygons and Quadrilaterals. See more at:

1. Interior Angles in Convex Polygons:
[ Ссылка ]

2. Exterior Angles in Convex Polygons:
[ Ссылка ]

3. Parallelograms:
[ Ссылка ]

4. Quadrilaterals that are Parallelograms:
[ Ссылка ]

5. Parallelogram Classification:
[ Ссылка ]

6. Trapezoids:
[ Ссылка ]

7. Kites:
[ Ссылка ]

8. Quadrilateral Classification:
[ Ссылка ]

Watch the whole series of CK-12's Basic Geometry videos: [ Ссылка ]

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