What you need to know
To achieve 100+ you need to:
recognise angles, and find missing angles, where they meet at a point or are on a straight line or are vertically opposite
find unknown angles in any triangle, quadrilateral or regular polygon.
- Angles that meet at a point add to 360°.
- Angles on a straight line add to 180°.
- Angles within a triangle add to 180°.
- Angles within a quadrilateral add to 360°.
- Angles that are vertically opposite are equal in size.