Warm Up:Pg. 72 # 28 to 32

Circle: set of all points (same distance) from a given center

Circles have many parts:Segments, lines, angles all can be parts of a circle!

Concentric circles:

Congruent circles:

5 cm

5 cm

1.6 Circles pg. 67 to 72

Arcs of circles:

Three types:Semicircle (endpoints are endpoints of diameter) (3 letters)

Minor arc (named by 2 points, less than half a circle)

Major Arc (named by 3 points, more than half a circle--middle point shows direction)

endpoints

x

A

B

C

D

Dont' forget the arc symbol over the points when you name the arc!

Central Angle of a Circle:(angles in a circle thay use the

center as it's vertex)

What happens when they want to know the measure of the arc and you are not sure what fraction of the circle it is?

Measure?

Measure of the arc = measure of the central angle

Arc

Central Angle

23°337°

Formed by 2 radii, vertex at center of circle

23°

The distance around the circle one time is 360°halfway around is 180° and so on.

Define terms:

Radius:

Diameter:

Chord:

Tangent:

Point of Tangency

A

Z

S

Q

W

E

C

V

GH

N

Name the following:Any chords, central angles, arcs,

diameters, radii, tangents

D

H

JK

N

M

L

G

A

FR

T