Khan Academy on a Stick
Quadrilaterals
Not all things with four sides have to be squares or rectangles! We will now broaden our understanding of quadrilaterals!

Quadrilateral Overview
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Basics of quadrilaterals including concave, convex ones. Parallelograms, rectangles, rhombi and squares

Quadrilateral Properties
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Quadrilateral Properties

Proof  Opposite Sides of Parallelogram Congruent
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Proving that a figure is a parallelogram if and only if opposite sides are congruent

Proof  Diagonals of a Parallelogram Bisect Each Other
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Proving that a quadrilateral is a parallelogram if and only if its diagonals bisect each other

Proof  Opposite Angles of Parallelogram Congruent
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Showing that opposite angles of a parallelogram are congruent

Proof  Rhombus Diagonals are Perpendicular Bisectors
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Proving that the diagonals of a rhombus are perpendicular

Proof  Rhombus Area Half Product of Diagonal Length
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Showing that we can find the area of a rhombus by taking half the product of the lengths of the diagonals

Area of a Parallelogram
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Showing that the area of a parallelogram is base times height

Whether a Special Quadrilateral Can Exist
Proving whether a special quadrilateral can exist

Rhombus Diagonals
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Proof that the diagonals of a rhombus are perpendicular bisectors of each other
Quadrilaterals
Not all things with four sides have to be squares or rectangles! We will now broaden our understanding of quadrilaterals!