1. Section 5.2 – Central Angles and Arcs Objective To find the length of an arc, given the central angle Glossary Terms Arc – a part of a circle Central angle – an angle whose vertex lies at the center of a circle

2. Central Angles and Arcs central angle arc

3. Length of an Arc The length of any circular arc, s, is equal to the product of the measure of the radius of the circle, r, and the radian measure of the central angle,  that it subtends. s = r 

4. Find the length of an arc that subtends a central angle of 42° in a circle with a radius of 8 cm. First change 42° to radians 42° x  180 = 77 30 Now use the arc length formula: s = r  s = 8 x 77 30 s = 8 x.733 s = 5.864

5. Assignment page 251 – 254 –# 16 – 27, 34, 41, 45