Homework Help: math (algebra honors) #2

Posted by K.S. on Sunday, February 27, 2011 at 5:55pm.

If the radius of a circle is increased by 6 cm, the new area is 121 (pi) cm^2. Find the radius of the original border using factoring.

math (algebra honors) #2 - jesse, Monday, November 19, 2012 at 10:08pm
the answer is 5 by common sense, i would reevaluate your schools "honours" program

the area of a circle is pi(r^2)

therefore pi(x+6)^2=121pi
now just solve
(x+6)^2=121
x+6=11
x=5
math (algebra honors) #2 - jesse, Monday, November 19, 2012 at 10:09pm
the answer is 5 by common sense, i would reevaluate your schools "honours" program

the area of a circle is pi(r^2)

therefore pi(x+6)^2=121pi
now just solve
(x+6)^2=121
x+6=11
x=5

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