The area of circle O is added to its diameter. If the circumference of circle O is then subtracted from this total, the result is 6. What is the radius of circle O?  Choose the correct choice from the following choices:
A) –2/pi  B) 2  C) 3  D) 4  E) 5
pi*r^2 + 2r -2*pi*r =6   Simplifying the equation: pi*r(r-2)+2r=6   Without much algebraic: We can Test the answers quickly, then 3 is the only possible answer that will eliminate pi from equation.   Answer is 3
<result>C</result>
The area of circle O is added to its diameter. If the circumference of circle O is then subtracted from this total, the result is 6. What is the radius of circle O?