Answer: 
Step-by-step explanation:
<u>Given equation</u>

<u>Expand the parenthesis and apply the distributive property</u>


<u />
<u>Combine like terms</u>


<u>Subtract 8 on both sides</u>


<u>Divide 2 on both sides</u>


Hope this helps!! :)
Please let me know if you have any questions
Answer:
The answer is 50.27. I'm sorry if it's wrong.
Step-by-step explanation:
A=πr2=π·42≈50.26548