Warm-up

10.1 Lines and Segments that Intersect Circles

• Write a definition for each of the five terms based on the picture below.

CircleThe set of all points in a plane at a given distance from a point (Center)

Radius - the distance from the center to

each of the points on the circle.

CircumferenceCircumference – the linear distance around the edge of a circle. Diameter = 2 x radius

Circumference Investigation

1) Find a circular object. 2) Measure the circumference and diameter. 3) Find C/D4) Record your results on the board. Do this a few times.

• http://en.wikipedia.org/wiki/File:Pi-unrolled-720.gif

Congruent Circles

Two or more circles have the same radius

Concentric CirclesTwo or more coplaner circles that share the

same center.

Matching

Tangent Conjecture

A tangent to a circle is perpendicular to the radius drawn to the point of tangency

Tangent Segments

A line segment that lies on a tangent line with one endpoint at the point of tangency

Given Segments SR and ST are tangentProve SR = ST

Tangent Segment ConjectureTangent segments to a circle from a point

outside the circle are congruent.

Classify each polygon.1) Triangle ANG 2) Quadrilateral ANGE

Tangent Circles

Two circles that are tangent to the same line at the same point.

Find the measure of T