Bellwork

iPads off; sticker side up. Compare your homework

(definitions) with the person sitting next to you. Discuss any that you have different and decide whose definition describes the polygon best.

Circles

REVIEW

1. Find the midpoint of line segment AB if A(4,-1) and B(7, -6)

(5.5, -3.5)

2. U is the midpoint of line segment YZ. The coordinates of Y are (4,6) and the coordinates of U are (2,5). Find the coordinates of Z.

(0,4)

Circles

New Material

CircleA circle is the set of all points in a plane at a given distance (radius) from a given point (center).

RadiusA radius is a segment from the center point to an edge of a circle.

Formalize a definition using the examples and nonexamples.

DiameterThe diameter is a line segment containing the center of a circle with endpoints on the circle

Formulate a definition using the examples and nonexamples.

ChordA chord is a line segment whose endpoints lie on the circle.

DiameterPreviously defined.

A diameter is the longest possible chord.

Formulate a definition using the examples and nonexamples.

TangentA tangent is a line that intersects the circle only once.

Arc of a circleAn arc of a circle is two points on the circle and the continuous part of the circle between the points.

SemicircleA semicircle is an arc of a circle whose endpoints are the endpoints of a diameter.

Minor ArcA minor arc is an arc of a circle that is smaller than a semicircle.

Major ArcA major arc is an arc of a circle that is larger than a semicircle.

Major/Minor Arcs

Central AngleA central angle is an angle with its vertex in the center of a circle.

Concentric Circles

Two or more coplanar circles share the same center.