Maths · GCSE · Algebra

Equation of a circle

Equation of a circleFree8:56Heddy Score 3 of 7, below the standard
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What you need to know

  • A circle centred at the origin has equation x² + y² = r².
  • Take the positive square root of the constant to find the radius.
  • The diameter is twice the radius and the area is πr².
Heddy Score3/7, Below the standard
See the seven stars
  • 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 · passed. 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.
★ passed · ☆ pending · ✕ failed
Our students

Not enough students yet

Our own students' answers. These are what move ★7 Proven.
On YouTube

171K views · 2.59K likes · 1st Class Maths 313K subscribers

As reported by YouTube on 2026-11-02. Not part of the Heddy Score.
How the Heddy Score works

Why we picked it

The worked examples support practice with equation of a circle.

1st Class Maths on YouTubechecked 2026-10-18

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