Maths Circle Geometry

Eight rules needed for circle geometry. :) 

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  • Created by: Elliza
  • Created on: 30-05-11 12:49

Maths Circle Geometry

Simple Rules:

  • A triangle drawn from the two ends of a diameter will always make an angle of 90°
  • A tangent is a line that just touches a single point on the edge of a circle. It will always make an angle of exactly 90°.
  • Isosceles triangles formed by two radii don't have little 'tick' marks to remind you that they're the same - even though they are. 
  • A chord is any line drawn across a circle. No matter where you draw a chord, the line that cuts it in half will go through the centre, making it a diameter.
  • Any triangles drawn from a chord will have the same angle where they touch the edge of the circle. Opposite sides of the chord add up to 180°
  • The angle made at the centre of a circle is exactly double the angle made at the edge of the circle
  • Opposite angles of a cyclic quadrilateral add up to 180°
  • The two tangents drawn from an outside point are always equal in length, so they create two congruent right angled triangles
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Thank yueee :)

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