(Use )

7). (2 points) [Extra credit]

Find the area of this quarter circle:
(a quarter-circle is 1/4 of a circle)

Area = __________

8). (2 points) [Extra credit]

Find the area of the shaded part of this figure. (the inside figure is a circle. Find the circle's radius)

Area = __________

9). (2 points) [Extra credit]

Find the area of this figure. The right end is a half-circle.
(Hint: Find the radius of the circle)

Area = __________