CPM Homework Help : GC Problem 8-106

A spinner with two diameter lines intersecting each other. The internal angle the diagonal lines create is 20 degrees. Your teacher has constructed a spinner like the one at right. He has informed you that the class gets one spin. If the spinner lands on the shaded region, you will have a quiz tomorrow. What is the probability that you will have a quiz tomorrow? Explain how you know.

Hint:

The measure of all the angles that share a vertex at the center of a circle must add to $360°$ .

More help:

Vertical angles - the angles formed on opposite sides of two intersecting lines - are congruent to one another.

Answer:

$\frac{320°}{360°}\approx0.89\%$