There is no illustration, so it is impossible to answer this question. I apologise.
Answer:
Could you state the question in the correct order?? Like is N supposed to be there?
The area of a circle is:

"r" being the radius and π being 3.14
14. The diameter is 12. So, to get the radius, we would need to halve it. So, the radius would be 6.
Now we plug in 6 for r and 3.14 for π which makes it

which equals 113.04
15. The diameter is 9, so to get the radius we need to halve it to get 4.5
Plug in 4.5 for r and 3.14 for π and we get

which equals 63.585
16. The diameter is 18, so to get the radius we need to halve it to get 9
Plug in 9 for r and 3.14 for π and we get

which equals 254.34
17. The diameter is 8, so to get the radius we need to halve it to get 4.
Plug in 4 for r and 3.14 for π and we get
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