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← 2.2 Loci

The involute of a polygon

Power Mechanics · Grade 10 · about 40 minutes

Unwinding a string from a square or triangle, why the curve is made of exact circular arcs, and how the radius grows at each corner.

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  • 6 sections of explanation, worked examples and diagrams
  • 1 practice task with hints and worked answers
  • A quiz that marks itself as you go
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Other lessons in this sub-strand

  1. What a locus is
  2. Constructing the basic loci
  3. The ellipse and its two foci
  4. The ellipse by concentric circles
  5. The ellipse by the trammel method
  6. What a cycloid is
  7. Constructing a cycloid
  8. Epicycloid and hypocycloid
  9. The involute of a circle
  10. The involute of a polygon
  11. The parabola by the rectangle method
  12. The parabola from focus and directrix
  13. The rectangular hyperbola
  14. The locus of a point on a two-link mechanism
  15. The locus of a point on a three-link mechanism
  16. Loci at work in power mechanics