Angles in triangles and quadrilateralsQuadrilaterals

Angles inside a shape are called interior angles. Interior angles in a triangle add up to 180°. Interior angles in a quadrilateral add up to 360°.

Part ofMathsAngle, symmetry and transformation

Quadrilaterals

You can use this fact to find missing angles.

Example

Find angle \(d\).

Quadrilateral shape with angles, 100degrees, 70degrees, 30degrees & unknown angle d

\(d = 360^\circ - (100^\circ + 70^\circ + 30^\circ\)

\(d = 160^\circ\)

This example shows an irregular quadrilateral.

There are specific facts about regular quadrilaterals that can help you find missing angles.