UNDERSTANDING QUADRILATERALS

Polygon

A simple closed curve made up of only line segments.

Convex Polygon

A polygon where no portions of its diagonals lie in the exterior.

Concave Polygon

A polygon that has at least one diagonal lying outside of it.

Regular Polygon

A polygon that is both equiangular and equilateral.

Equiangular Polygon

A polygon with all angles of equal measure.

Equilateral Polygon

A polygon with all sides of equal length.

Trapezium

A quadrilateral with at least one pair of parallel sides.

Isosceles Trapezium

A trapezium where the non-parallel sides are equal.

Kite

A quadrilateral with exactly two distinct pairs of consecutive sides of equal length.

Parallelogram

A quadrilateral with opposite sides that are parallel.

Rhombus

A parallelogram with all sides of equal length.

Rectangle

A parallelogram with all angles equal to 90 degrees.

Square

A rectangle with all sides of equal length.

Diagonals of a parallelogram

The diagonals bisect each other at the point of their intersection.

Exterior Angles of a Polygon

The sum of the measures of all exterior angles of any polygon is 360°.

Adjacent Angles in Parallelogram

In a parallelogram, adjacent angles are supplementary.

Opposite Angles in Parallelogram

In a parallelogram, opposite angles are equal.