Maths · GCSE · Geometry & Measures
Circle theorems: angles
gcse-math-g10aFree3:55Heddy Score 2 of 7, below the standardPlays from youtube-nocookie.com. No YouTube cookies until you press play.
What you need to know
- The angle at the centre is twice the angle at the circumference.
- The angle in a semicircle is 90°.
- Angles in the same segment are equal.
- Opposite angles in a cyclic quadrilateral add to 180°.
In this clip
0:36–4:31Circle theorems: anglesgcse-math-g10a4:31–6:44Circle theorems: tangents and chordsgcse-math-g10bHeddy ScoreSeven checks every clip must pass before students see it: trusted, on the map, accurate, focused, accessible, safe, and proven by students.2/7, Below the standard
- Trusted source · passed. The creator's own upload, live and playable here.
- On the map · not judged yet. A teacher watched it: it mainly teaches this map topic.
- Spec-true · not judged yet. Accurate, and right for the current UK specification.
- Focused · passed. One idea, short enough to watch in one go.
- Accessible · not judged yet. Good captions, clear sound and pictures.
- Safe for children · not judged yet. Right for 11 to 16 year olds, with no sales pitch.
- Proven · not judged yet. Earned from our students: they learn from it, find it helpful and watch it to the end.
Our students
How the Heddy Score worksNot enough students yet
Our own students' answers. These are what move ★7 Proven.Why we picked it
Clear Higher-tier walk-through of every circle theorem with worked examples; suits Year 10–11 Higher students.
1st Class Maths on YouTubechecked 2026-10-16