Answer:
113.081 mm²
Explanation:
A semicircle is the half part of a circle. And we know that the semicircle have 24 mm of diameter, and the radius is 24/2 = 12 mm. The small circle is inside the semicircle, so its diameter is equal to the radius of the semicircle, and its radius is 12/2 = 6mm
Now, consider π = 3.141, the area of the small circle is:
π•6² = 3.141 • 36 = 113.076 mm²
The area of the semicircle is (π•12²)/2 = (3.141•144)/2 = 226.151 mm²
Now, you just subtract the areas:
226.151 - 113.076 = 113.081 mm²