A quadrilateral is a shape with four sides.

There are six special quadrilaterals with different properties.

### Square

• A square has four sides of equal length.
• It has four right angles (90°).
• The opposite sides are parallel.
• The each other at right angles.

### Rectangle

• A rectangle has two pairs of equal sides.
• It has four right angles (90°).
• The opposite sides are parallel.
• The diagonals bisect each other.

### Parallelogram

• A parallelogram has two pairs of equal sides.
• It has two pairs of equal angles.
• The opposite sides are parallel.
• The diagonals bisect each other.

### Rhombus

• A rhombus has four sides of equal lengths.
• It has two pairs of equal angles.
• The opposite sides are parallel.
• The diagonals bisect each other at right angles.

### Trapezium

• A trapezium has one pair of parallel sides.

### Kite

• A kite has two pairs of equal sides.
• It has one pair of equal angles.
• The diagonals bisect at right angles.

## The sum of interior angles in a quadrilateral

The sum of interior angles in a quadrilateral is 360°.

This fact and the properties of quadrilaterals can be used to calculate angles.

### Example

Find angle . Question

Find the unknown angles.

The quadrilateral is a parallelogram. Opposite angles are equal. Angles in a quadrilateral add up to 360° and opposite angles are equal. 