Theorems based on circles and tangents

Theorems based on circles and tangents

 

Definition: A straight line which touches a circle at only one point is called a tangent to the circle and the point at which it touches the circle is called its point of contact.

  • A tangent at any point on a circle is perpendicular to the radius through the point of contact.
  • Only one tangent can be drawn at any point on a circle. However, from an exterior point of a circle two tangents can be drawn to the circle.
  • The lengths of the two tangents drawn from an exterior point to a circle are equal.
  • If two circles touch each other, then the point of contact of the circles lies on the line joining the centres.
  • If two circles touch externally, the distance between their centres is equal to the sum of their radii.
  • If two circles touch internally, the distance between their centres is equal to the difference of their radii.

 

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One response to this post.

  1. Posted by Anand Kumar on September 21, 2011 at 5:00 am

    its helpful to me to knou about tangents….
    but i had a problem in maths and i feel struggle to solve even a small problem..
    i need a list of important formulaes and basic formulaes,rules,theoram that help me to equip myself in maths

    Reply

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