Section+9.2+swann

=Section 9.2=

Objectives:

 * Define tangents and secants of circles
 * Understand the relationship between tangents and certain radii of circles
 * Understand the geometry of a radius perpendicular to a chord of a circle

Definitions:
exactly one point, which is also known as the point of tangency
 * Secant: A line segment of a circle that intersects the circle at two points
 * Tangent: A line segment on the intersecting the circle on its outside line in

of tangency if the line is tangent.
 * A line is perpendicular to a circle's radius that is drawn to the point

Radius and Chord Theorem:

 * The radius of a circle bisects the chord that it is perpendicular to.

Converse of Tangent Theorem:
circle's radius at its one endpoint falling on the circle's edge.
 * A line is tangent to a circle if that line is perpendicular to the

Theorem

 * The perpendicular bisector of a chord passes through the center of the circle.

Example:

Circle P has a radius of 6in. and PX is 2in. Line PR is perpendicular to Line AB at point X. Find AB. pythagorean theorem: (AX)^2+2^2=6^2 (AX)^2=6^2-2^2 (AX)^2=32 AX=16