Properties of Quadrilaterals

Honors Geometry Date:______Lessons 12.1 and 12.2 Obj: ______

Watch the video by going to the following site: https://www.khanacademy.org/math/geometry/circles/v/language-and-notation-of-the-circle

Vocabulary: Fill in the vocabulary term that corresponds with the given definition

Interior: set of all points inside the circle Exterior: set of all points outside the circle ______: Line segment that connects the center of the circle to any point on it. ______: Segment whose endpoints lie on a circle. ______: Chord that contains the center. ______: Line that intersects a circle at two points. ______: Line in the plane of a circle that intersects the circle in exactly one point. Point of Tangency: The point on the circle that the tangent line intersects.

Example – Identify each line or segment that intersects L.

Chord(s): Secant(s): Tangent(s): Diameter(s): Radii: Point of Tangency:

Theorems  All radii of a circle are equal.  If a line through the center of a circle is perpendicular to a chord, it also bisects the chord.  If a line through the center of a circle bisects a chord that is not the diameter, it is also perpendicular to the chord.  The perpendicular bisector of a chord of a circle contains the center of the circle.

Vocabulary: Congruent Circles: circles that have the same radii. Concentric Circles: coplanar circles with the same center.

Tangent Circles: coplanar circles that intersect at exactly one point. Internally Externally

Common Tangent: a line that is tangent to two circles.

Proof:

Given: LN^ FI in e G Prove: VFIN is isosceles N

L F I Theorems  If a line is tangent to a circle, then it is perpendicular to the radius drawn to the point of tangency.  If a line is perpendicular to a radius of a circle at a point on the circle, then the line is tangent to the circle.  If two segments are tangent to a circle from the same external point, then the segments are congruent.