Adv. Math

How do you do these problems???


What is the radius of a circle that its area is 254.5 square inches???


What is the diameter of a circle if its area is 132.7 square meters??



I don't understand this because of the thing that says "square"

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asked by Kenya
  1. area of circle = pi(r^2)

    so for the first one :

    254.5 = pi(r^2), divide both sides by pi
    81 = r^2 , now take the square root of both sides
    9 = r

    do the second one the same way, double the answer you get for r to get the diameter.

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    posted by Reiny
  2. For an explanation of "square" in a circle, check this site.

    http://www.mathgoodies.com/lessons/vol2/circle_area.html

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