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Quadrilateral_proofs_angles

Not all things with four sides have to be squares or rectangles! We will now broaden our understanding of quadrilaterals.

Quadrilateral_types

Not all things with four sides and 90 degree angles are squares or rectangles! Sometimes the angles in these 4-sided shapes are less than (or greater than) 90 degrees, causing them to have a slightly odd shape. These are called quadrilaterals and come in a few different varieties. In this tutorial, you'll learn about them.