Trig help. So confused

Question

A central angle of 60° is inscribed in a circle with a radius of 7inch. What is the length of the intercepted arch? 

A. 8.5 inch

B. 420 inch

C. 7.33 inch

D. .19 inch

E. 7 inch

Answer 1

Since a full circle is 360º, we can treat the 60° portion as a fraction of the full circumference.  Simply multiply the circumference by 60/360:

 

60/360 · 2π·7 = 7.33 inches (Option C)

Answer 2

arc length = (central angle in radians) * (radius of the circle)

 

central angle = 60° = 60 * pi/180 radians

 

arc length = (60*pi/180) * 7

 

arc length = 7.33 inches