10.6 circles and arcs.notebook
3/20/17 - Warm Up Problem
Write a good definition of a circle.
March 20, 2017
10.6 circles and arcs.notebook
March 20, 2017
Section 10.6 - Circles and Arcs
Goals:
identify special segments in circles, central angles, and arcs
find the measure of central angles and arcs
Circle: set of all points in a plane that are equidistant from a given point (center).
Radius: segment from the center to a point on the circle.
Diameter: segment across a circle through the center
2 * radius = diameter
center
10.6 circles and arcs.notebook
Naming Parts of a Circle
Name the circle.
Name all the radii of the circle.
Name the diameter of the circle.
If the radius of this circle was 5 in., what does the diameter equal?
March 20, 2017
10.6 circles and arcs.notebook
March 20, 2017
Measures of Central Angles
Central Angle : an angle whose vertex is the center of the circle.
­its sides are two radii
All of the central angles of
a circle must add up to
360 degrees
Find the measure of each central angle.
84o
35o
10.6 circles and arcs.notebook
March 20, 2017
Finding Arc Measures
A
Arc: part of the edge of a circle
Measure of an Arc: an arc's
measure equals the measure of
its corresponding central angle
86o
B
D
C
o
Semicircle: an arc that is exactly 180
o
Minor Arc: an arc that is smaller than 180
o
Major Arc: an arc that is greater than 180
Classify and name the pink arc.
10.6 circles and arcs.notebook
March 20, 2017
Measure of an arc = Measure of its central angle
C
Find the measure of each arc.
A
55o
F
D
B
10.6 circles and arcs.notebook
Measure of an arc = Measure of its central angle
Find each measure:
March 20, 2017
10.6 circles and arcs.notebook
Assignment:
pg. 654
(9-23)
9,10,11 - just name one of each
March 20, 2017