Find the radius of a circle if it's area is 706.9 square millimeters?

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Answer 1 · 2018-03-15T13:45:01

See a solution process below:

The formula for the area of a circle is:

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Substituting #706.9"cm"^2# and approximating #pi# as and then solving for #r# gives:

#706.9"cm"^2 ~= 3.14 * r^2#

#(706.9"cm"^2)/color(red)(3.14) ~= (3.14 * r^2)/color(red)(3.14)#

#225.1"cm"^2 ~= (color(red)(cancel(color(black)(3.14))) * r^2)/cancel(color(red)(3.14))#

#225.1"cm"^2 ~= r^2#

#sqrt(225.1"cm"^2) ~= sqrt(r^2)#

#15.0"cm" ~= r#

The radius of the circle is approximately 15 centimeters.