Posted by Kenya on Wednesday, May 14, 2008 at 11:20pm.
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"

Adv. Math  Reiny, Thursday, May 15, 2008 at 12:08am
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.

Adv. Math  Ms. Sue, Thursday, May 15, 2008 at 11:27am
For an explanation of "square" in a circle, check this site.
http://www.mathgoodies.com/lessons/vol2/circle_area.html
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