The area of a circle is subtracted from its diameter, and the circumference is then added to this total, the result is 0. What is the radius of the circle? Choose the correct choice from the following options.
A) 2*pi  B) pi  C) 1  D) 2  E) 3
The equation is; diameter - Area + Circumference = d - A + C = d - pi * r^2 + 2 * pi * r = 2r - pi * r(r + 2).   By plugging in the answers we can test the answers quickly; then, 2 is the only possible answer.   Answer: 2
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The area of a circle is subtracted from its diameter, and the circumference is then added to this total, the result is 0. What is the radius of the circle?