To find the area or circumference of any circle, you need to use pi. So, if we are trying to fine the area of a <em>semicircle, </em>you use the the formula:
πr²/2
So, if the radius is 8.5,
8.5 · 3.14 = 26.69
Now we divide it by 2.
26.69 = 13.345
Since the question is asking to round to the hundredths, the answer will be 13.35 millimeters.
