10.3 Central Angles and Arcs Flashcards
Central Angle
An angle whose vertex is the center of the circle
Arc
An unbroken part of a circle
Minor arc
On circle P, if angle APB is less than 180 degrees, then the points A and B together with the points on circle P that lie in the interior of angle APB
Measure of a Minor Arc
Measure of its central angle
Semicircle
If the endpoints of the arc are the endpoints of a diameter, then the arc is a semicircle and its measure is 180 degrees
Major Arc
On circle P, if the measure of angle APB is less than 180 degrees, then the points A and B together with the points on circle P that lie in the exterior of angle APB
Measure of a Major Arc
Difference between 360 degrees and the measure of its associated minor arc
Adjacent Arcs
Two arcs of the same circle that intersect at exactly one point
Arc Addition Postulate
The measure of an arc formed by two adjacent arcs is the sum of the measures of the two arcs
Congruent Arcs
In the same circle or in congruent circles, two arcs are congruent if and only if they have the same measure
Thm. 10.4
In the same circle or congruent circles, two arcs are congruent if and only if their central angles are congruent