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anonymous

  • 5 years ago

Which of these is the closest approximation of the area of a circle with a radius of 3.125 cm ? a.)about 15 cm2 b.)about 30 cm2 c.)about 20 cm2 d.)about 25 cm2

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  1. anonymous
    • 5 years ago
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    Area = pi times radius squared. 3.125 is roughly 3, and 3 squared is 9. pi is roughly 3, and 9 times 3 is 27. Since you estimated both numbers low, your actual answer will be greater than 27, so B.

  2. anonymous
    • 5 years ago
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    its b. the formula is PI * Radius squared. if you do some really rough rounding, PI = 3. now 3.125 is about 3. so using the formula, you do: 3*(3 squared) which is ABOUT 27. now you know that PI is a little bit larger than the number you just used for PI (the estimated of PI), so find a numbr a litle but larger than 27. That is 30.

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