Warm-up

10.1 Lines and Segments that Intersect Circles

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

Circle

The 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.

Circumference Circumference – 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/D 4) 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 Circles Two 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 tangent Prove SR = ST

Tangent Segment Conjecture Tangent 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