Skip Navigation Links
Tangent of a Circle
To enroll in any of our courses, click here
Tangent of a Circle
A tangent to a circle is a line that intersects the circle in exactly one point.
People who saw this lesson also found the
following lessons useful:
Solution of Problems involving Quadratic Equation
Probability: Examples
Sphere: Surface Area & Volume
Quadratic Equation: Determining an Unknown when Roots are given
Example: Find the length of the tangent drawn from a point whose distance from the center of a circle is 7 cm. Given that the radius of the circle is 5 cm.
Solution: Let A be the given point, O be the centre of the circle and AT be the length of tangent from A. Then, OA = 7 cm and OT = 5 cm.
Since tangent to a circle is always perpendicular to the radius through the point of contact.
Therefore, OTA = 90 degree

In right triangle OTA, we have
OA2 = OT2 + AT2
72 = 52 + AT2
AT2 = 72- 52
= (7 - 5) ( 7 + 5)
= 24
AT = 26 cm
Hence, length of tangent from A = 26 cm.
As many of you know, Winpossible's online courses use a unique teaching method where an instructor explains the concepts in any given area to you in his/her own voice and handwriting, just like you see your teacher explain things to you on a blackboard in your classroom. All our courses include teacher's instruction, practice questions as well as end-of-lesson quizzes for practice. You can enroll in any of our online courses by clicking here.

The format of Winpossible's online courses is also very suitable for teachers who are using an interactive whiteboard such as Smartboard on Promethean in their classrooms, because the course lessons can be easily displayed on such interactive whiteboards. Volume pricing is available for schools interested in our online courses. For more information, please contact us at

 Copyright © Winpossible, 2010 - 2011
Best viewed in 1024x768 & IE 5.0 or later version