Maths · KS3 Y8 · Geometry & Measures

Area of a circle

m127Free1:47Heddy Score 2 of 7, below the standard

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What you need to know

  • The area of a circle is π × radius squared.
  • Halve the diameter before squaring.
  • Leave the answer in terms of π when an exact value is asked for.

In this clip

8:33–9:37Rearranging simple formulaem71
9:37–12:43Solving linear inequalitiesm73
14:00–15:57Averages from frequency tablesm171
17:06–18:06Constructing bisectorsm135
18:06–20:36Linear graphs y = mx + cm17
21:35–23:22Area of a circlem127
26:01–26:58Reverse percentagesm52
26:58–28:18Laws of indicesm41
30:48–32:24Inverse proportionm103
32:24–34:21Speed, distance, timem96
34:21–35:52Scatter graphs & correlationm20
37:34–38:52Pythagoras: the hypotenusem136
40:11–42:28Column vectorsmh15
46:09–48:15Venn diagrams for probabilitym157
55:24–57:38Simultaneous equationsm19
61:55–63:41Compound interestmh12
63:41–66:11Trigonometry first stepsmh2
68:28–70:43Graphs of quadraticsm85
70:43–72:19Locigcse-math-g2c
72:19–74:29HCF & LCM by prime factorsm54
74:29–76:18Volume of pyramids, cones and spheresgcse-math-g17b
83:26–84:53Tree diagramsmh17
91:35–94:32Density and pressuregcse-math-r11b
112:22–113:53Negative scale factorsgcse-math-g7c
159:44–163:10Histogramsgcse-math-s3a
169:09–171:56Algebraic proofgcse-math-a6c
173:39–176:10Similar shapes: areas and volumesgcse-math-g19b
193:10–194:55Turning points by completing the squaregcse-math-a11c
203:02–206:42Tangent to a circlegcse-math-a16b
210:10–213:40Iterationgcse-math-a20
Also coversCalculator fluencym44
Also coversEstimating before calculatingm32
Also coversFrequency polygonsmh19
Also coversCalculating in standard formm48
Also coversParallel lines on graphsm79
Also coversSurface area of pyramids, cones and spheresgcse-math-g17c
Also coversExponential graphsgcse-math-a12c
Also coversAlgebraic fractionsgcse-math-a4g
Also coversArea under a graphgcse-math-a15b
Also coversGeometric proofgcse-math-g6
Also coversVector proofsgcse-math-g25b
Also coversTransforming graphsgcse-math-a13
Heddy Score2/7, 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.
★ passed · ☆ pending · ✕ failed
Our students

Not enough students yet

Our own students' answers. These are what move ★7 Proven.
How the Heddy Score works

Why we picked it

1st Class Maths' long Higher revision video working through a question booklet; many chapters are only links, so the timed set keeps the clearly titled ones.

1st Class Maths on YouTubechecked 2026-10-16