Problem:
In an arcade game, the "monster" is the shaded sector of a circle of radius cm, as shown in the figure. The missing piece (the mouth) has central angle . What is the perimeter of the monster in cm?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
The shaded sector has central angle , or of . Thus the perimeter consists of of the circumference of a circle of radius , plus radii of the circle. Thus the length is