Transcript Find Arc measures - East Pennsboro High School

FIND ARC MEASURES
10.2
Vocab

Central Angle: an angle where the vertex is at the
center of the circle.
And the vocab continues



Minor arc: an angle inside a circle whose measure is
less than 180°. (They only need 2 letters to be
named but can also have 3 letters.)
Major arc: an angle inside a circle whose measure is
greater than 180° or the arc that is not the minor
arc. (They require 3 letters to be named)
Semicircle:
 Half
a circle
Name the minor and major arc

I’m a minor!
AB

ADB
I’m a major!
Arc Addition postulate
This theorem allows us to add arcs
Find the indicated arc
Find the indicated arc
360 – 90 = 270º
Find the indicated arc
360 ÷3 = 120º
Finding measures of arcs, where EB is a
diameter
75º
180-35 = 145º
75 + 35 = 110º
360 – 110 = 250º
35o
75o
Word Problems
306o
306
360 – 306 = 54º
54º
180 +54 = 234º
180º
Congruency



Circles are said to be congruent if and only if their
radii are the same.
Arcs are considered to be congruent if they are the
same measure and the circles they are contained in
are also congruent.
2 arcs of the same measure in the same circle are
considered congruent.
Congruent?
Congruent?
mCBD = 124.5
mCBD = 124.5
Page 661 #1 - 18