Tangent Lines in Circles
- Author:
- Austin Williams, soundmanbrad
At a 90 degree angle, tangent lines will intersect the circle at exactly one point, this is called the Point of Tangency.
Since tangent lines help us create right triangles, we can use the Pythagorean Theorem to determine lengths of unknown sides in a right triangle.
See below as a sample problem where the legs of this right triangle are given and we would want to find the hypotenuse, which is approximately 8.1 units.
Two tangent lines to a circle will need to have congruent measures from some external point if they are both going to have a point of tangency at 90 degrees.