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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.) - PowerPoint PPT Presentation
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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
AB
ADB
I’m a major!
I’m a minor!
Arc Addition postulate
This theorem allows us to add arcs
Find the indicated arc
Find the indicated arc
360 – 90 = 270º360 – 90 = 270º
Find the indicated arc
360 360 ÷3 ÷3 = 120º= 120º
Finding measures of arcs, where EB is a diameter
75º
180-35 = 145º75 + 35 = 110º360 – 110 = 250º
75o
35o
Word Problems
306360 – 306 = 54º
54º
180 +54 = 234º
180º
306o
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?
= 124.5 = 124.5
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