GCSE Maths (AQA)

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Tangents Meeting

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Geometry and Measures Properties and Constructions

Tangents Meeting

4:04 Circle Theorems
Spec G10
Previous Angle Between a Tangent & the Radius Next Prisms & Cylinders
  • Two tangents drawn from a point to a circle are equal in length
  • The theorem can be proven using congruent triangles and the relation between a radius and a tangent
  • Draw a line from the center of the circle to where the tangents meet to create two triangles
  • Deduce that the angles where the radii meet the tangents are 90 degrees
  • State the relation between the two radii (OA = OC)
  • Show that the two triangles are congruent using the RHS condition
  • Deduce that the other side lengths are equal (AB = CB)
  • Prove the theorem that the two tangents have the same length since they originate from the same point

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