**In Class**today we solved area problems involving sectors, segments and anuluses.

The trick in many area problems is to make a plan and think of ways to add and subtract calculable areas to find difficult to find areas. For example, a segment is just a sector minus a triangle.

One of the tasks students are assigned today is to find the measure of an angle given information about the area of a sector:

So, We would compare the area of the sector to the area of the circle

, so since we have

Now, this means that the shaded area, as a fraction of the total area of the circle is

So, since the shaded area is 5/24 of the area of the circle, the central angle must make up 5/24 of 360 degrees, so we find

So, the value of , or the central angle of the sector is

**Tonight's assignment **is to complete 8.6 on p. 439: 1-12, 17-22