Arectangle is placed around a semicircle as shown below. the length of the rectangle is 18mm . find the area of the shaded region. use the value 3.14 for π , and do not round your answer. be sure to include the correct unit in your answer.

in advance for the answer

In the picture, it is a semicircle, so you have to remember to divide the area by 2.
The diameter of the circle is 18, so the radius is 9. Using the formula, I'll find the area.
9²π=81π= 254.34÷2= 127.17
Now finding the radius actually help, because that semicircle's height is its radius, which is 9.
18 ×9 = 162
Now I'm going to find the shaded area.
162 - 127.17 = 34.83 mm²