Recall some facts from your Chapter 1 investigation of radian measure.  

1. How many radians are in a full circle?

   Hint (a):

   What is the ratio of the circumference of a circle to its radius?

2. How many radians are in half a circle?

3. What are the radian measures that correspond to the following degree measures?

   1. $30º$ 

   2. $45º$ 

   3. $60º$ 

   Hint (c):

   Review your work from problem 1-111.