A quadrilateral is a polygon with 4 sides and 4 corners.
The word ‘quadrilateral’ comes from ‘quad’ meaning ‘4’ and ‘lateral’ meaning ‘of sides’.
The interior angles of quadrilaterals add to 360 degrees.
Any quadrilateral with 4 right angles is a rectangle.
A quadrilateral with 4 right angles and 4 equal length sides is a square. The area of a square is equal to the length of one side to the power of two (length squared).
The perimeter of a square is 4 times the length of one side.
Quadrilaterals with 2 sets of parallel side are called parallelograms.
A rhombus is a quadrilateral with four sides of the same length. A diamond shape is a good example of a rhombus.
A convex (outward) quadrilateral with one pair of parallel sides is known as a trapezoid in the US and a trapezium in other parts of the world. In both instances it comes from a Greek word meaning ‘a little table’.
A kite quadrilateral features 2 pairs of adjacent sides that are of equal length (much like a kite you can fly in the sky).
