SOLUTION: Find the radius of a circle with an area of 100in^2 (using quadratic equations)

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Question 1194390: Find the radius of a circle with an area of 100in^2 (using quadratic equations)
Found 2 solutions by ikleyn, MathTherapy:
Answer by ikleyn(52778)   (Show Source): You can put this solution on YOUR website!
.

     = 100  in^2  is your area equation, with the unknown radius "r".


From this equation.

     = 

and

    r =  =  = use your calculator = 5.642  inches  (rounded).    ANSWER

Solved.



Answer by MathTherapy(10551)   (Show Source): You can put this solution on YOUR website!
Find the radius of a circle with an area of 100in^2 (using quadratic equations)
Quadratic equation formula? WHY?
Anyway, we get: 

Quadratic equation formula: , where: 

Should be pretty easy for you to substitute and calculate to find your answer, after IGNORING the negative value.
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