Quadrilaterals

Quadrilateral Overview

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

Quadrilateral Properties

Quadrilateral Properties

Proof - Opposite Sides of Parallelogram Congruent

Proving that a figure is a parallelogram if and only if opposite sides are congruent

Proof - Diagonals of a Parallelogram Bisect Each Other

Proving that a quadrilateral is a parallelogram if and only if its diagonals bisect each other

Proof - Opposite Angles of Parallelogram Congruent

Showing that opposite angles of a parallelogram are congruent

Proof - Rhombus Diagonals are Perpendicular Bisectors

Proving that the diagonals of a rhombus are perpendicular

Proof - Rhombus Area Half Product of Diagonal Length

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

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

Proof that the diagonals of a rhombus are perpendicular bisectors of each other