Learning Target: I can find the measures of central angles and arcs. I can find circumference and arc length.
A CIRCLE is the set of all points equidistant from a given point called the center. Circle P P
A CENTRAL ANGLE of a circle is an angle with its vertex at the center of the circle. Central angle
An arc is a piece of a circle’s circumference. Arc
One type of arc, a semicircle, is half of a circle. P A C Semicircle ABC m ABC = 180 B
A minor arc is smaller than a semicircle. A major arc is greater than a semicircle.
A C D minor arcs E O AC CE DE AD
A C D semicircles E O ACE CAD
A C D major arcs containing point A E O ACD CEA DEA ADC
A C D central angles containing D E O AOD DOE
A C D radius E O AO DO EO CO
A C D diameter E O AE DC
The measure of a central angle is equal to its intercepted arc. 53 o O P R m ROP = 53° m RP = 53°
Find the measure of each arc. 1. BC = 32 ° 2. BD = 90 ° 3. ABC = 180 ° 4. AB = 148 ° 1. BC = 2. BD = 3. ABC = 4. AB =
The circumference of a circle is the distance around the outside of the circle. or
The arc length of a circle is the length of an arc; a piece of the circumference. or
Concentric Circles are circles within the same plane (coplanar) that have the same center.