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Formula
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Area of circle = πr²
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Find Area of circle
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Area of circle = 3.15 x 3²
Area of circle = 28.26 unit²
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Answer: Area = 28.16 unit²
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Answer:
and 
Step-by-step explanation:
when you solve for r in the given equation, you need to apply the square root property, which gives positive and negative answers (both should therefore be considered):

then you need to include these two possible solutions:
and 

<u>Answer</u><u>:</u>
<u>a.</u><u> </u><u>7</u>
Hope you could understand.
If you have any query, feel free to ask.