Tangents Tangent - A line in the plane of a circle that intersects the circle in exactly one point. Point of Tangency – The point of intersection between the circle and the tangent.

Tangents Theorem 10.9 If a line is tangent to a circle, it is  to the radius drawn to the point of tangency. Theorem 10.10 If a line is  to a radius of a circle at its endpoint on the circle, it is tangent to the circle.

Tangents Theorem 10.11 If two segments from the same exterior point are tangent to a circle, then they are congruent.

is a tangent to at point D. Find a. Answer: 15 Example 5-1c

a. Determine whether is tangent to Answer: yes Example 5-2e

b. Determine whether is tangent to Answer: no Example 5-2f

ALGEBRA Find a. Assume that segments that appear tangent to circles are tangent. Answer: –6 Example 5-3d

Triangle NOT is circumscribed about Find the perimeter of NOT if Answer: 172 units Example 5-4c