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! I’m a major!
Arc Addition postulate This theorem allows us to add arcs
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 75o 75 + 35 = 110º 35o 360 – 110 = 250º
Word Problems 306o B 306 c 360 – 306 = 54º 180 +54 = 234º A 54º 180º D
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.