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
You can use this fact to find missing angles.
Find 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.