The answer to the question is a. The formula for finding the area of a circle is [tex]A= \pi r^2
[/tex]. So, The radius is 6. So, You can now do 6 to the power of 2 getting you an answer of 36 times pi=area. Now, For the area of the rectangle do length times the width which is 12 times 18 gets you 216. Then, the equation to get you your answer should be 216-36pi. NOT SO FAST almost forgot about the circle being half so divide the 36 and you get 18. So, the answer is ACTUALLY D. 216-18pi.
