Angles: GCSE Maths revision
Angle facts are free marks if you state the reason. Learn the names: corresponding, alternate, co-interior, vertically opposite, and the 180° / 360° rules.
Facts to quote
- Angles on a straight line sum to 180°
- Angles around a point sum to 360°
- Angles in a triangle sum to 180°
- Corresponding angles are equal (F shape)
- Alternate angles are equal (Z shape)
- Co-interior angles sum to 180° (C shape)
Try these questions
Cover the answers and have a go first. Worked solutions are underneath.
Two angles on a straight line. One is 63°. The other?
Angles in a triangle are 40° and 65°. The third?
Corresponding angle to 110° is?
Co-interior with 110° is?
Common mistakes
- Calling co-interior angles equal.
- Missing the reason on the answer line — “because they are alternate” scores the mark.
Answers and working
Frequently asked questions
Do I have to name the angle fact?
Yes, if the question says “give a reason”. Use the official wording from the list above.
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