Interior and exterior angles

A polygon is simply a shape with three or more sides and angles. Quadrilaterals are 2D shapes with four sides and angles.

There are six special quadrilaterals with different properties.

Square

A square with dotted lines from corner to corner, showing a right angle where the lines cross.
  • A square has four sides of equal length.
  • It has four right angles (90°).
  • The opposite sides are parallel.
  • The diagonals bisect each other at right angles.
  • The exterior angles of a square are each 90°.

Rectangle

A rectangle with dotted lines from corner to corner, showing a right angle in each corner.
  • A rectangle has two pairs of equal sides.
  • It has four right angles (90°).
  • The opposite sides are parallel.
  • The diagonals bisect each other.
  • The exterior angles of a rectangle are each 90°.

Parallelogram

A parallelogram with dotted lines from corner to corner. It has two pairs of equal angles, coloured yellow and green.
  • A parallelogram has two pairs of equal sides.
  • It has two pairs of equal angles.
  • It has two pairs of equal exterior angles.
  • The opposite sides are parallel.
  • The diagonals bisect each other.

Rhombus

A rhombus with dotted lines from corner to corner, showing a right angle where the lines cross.  It has two pairs of equal angles, coloured yellow and green.
  • A rhombus has four sides of equal lengths.
  • It has two pairs of equal angles.
  • It has two pairs of equal exterior angles.
  • The opposite sides are parallel.
  • The diagonals bisect each other at right angles.

Trapezium

A trapezium with one pair of parallel sides.
  • A trapezium has one pair of parallel sides.

Kite

A kite with dotted lines from corner to corner, showing a right angle where the lines cross. It has one pair of equal angles, coloured green.
  • A kite has two pairs of equal sides.
  • It has one pair of equal angles.
  • One diagonal is bisected at right angles by the other.