Review what you know about the angles and arcs of circles below. 

1. A circle is divided into nine congruent sectors. What is the measure of each central angle?

   Hint (a):

   Recall that a whole circle is $360°$.

2. In the diagram at right, what are $m\overarc{ AED }$ and $m∠C$ if $m∠B = 97°$?

   Hint (b):

   Refer to the Math Notes in this lesson.

   More Help (b):

   Notice the relationship between $m∠B$ and $m∠C$.

   

3. In $⊙C$ at right, $m∠ACB = 125°$ and $BC = 8$ units. What are $m\overarc { A B }$ and the length of $\overarc { A B }$? What is the area of the smaller sector?

   Hint (c):

   What portion of the circumference is $\overarc { A B }$?

   More Help (c):

   Use the same method as above to find the area of the smallest sector.