SOLUTION: The area of a circle can be shown as: A=Pi(x^2-20x+100) Use factoring to find the expression for the radius of a circle. this equation factors to (x-10)(x-10) so the expression

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: The area of a circle can be shown as: A=Pi(x^2-20x+100) Use factoring to find the expression for the radius of a circle. this equation factors to (x-10)(x-10) so the expression      Log On


   

Question 29248: The area of a circle can be shown as:
A=Pi(x^2-20x+100)
Use factoring to find the expression for the radius of a circle.
this equation factors to (x-10)(x-10)
so the expression for the radius of a circle is r=(x-10)
If the are of the circle is 16pi^2ft What is the value for x?
A=pir^2
16pi^2=pi(x-10)^2 and I am back where I started from. Thank you for the help.
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You're doing fine so far...one question though - did you mean to write 16%28pi%29%5E2ft or 16%28pi%29sq.ft.???
I am assuming you meant the latter16%28pi%29sq.ft.
So, you would have:
16%28pi%29+=+%28pi%29%28x-10%29%5E2 Divide both sides by %28pi%29
16+=+%28x-10%29%5E2 Take the square root of both sides. Use only the positive results.
4+=+x-10 Add 10 to both sides.
x+=+14