SOLUTION: this accuplacer sample question is driving me nuts: two concentric circles have the same center, and the radius of the larger circle is R. If the radius of the smaller circle is 3

Algebra ->  Volume -> SOLUTION: this accuplacer sample question is driving me nuts: two concentric circles have the same center, and the radius of the larger circle is R. If the radius of the smaller circle is 3       Log On


   

Question 305070: this accuplacer sample question is driving me nuts: two concentric circles have the same center, and the radius of the larger circle is R. If the radius of the smaller circle is 3 units less than R, which represents the area of the shaded region?(the shaded region is the "doughnut" formed between the two circles) The answer given is
Pi(R-3)^2. But doesn't that give us the area of the smaller circle only? MY answer is PiR^2 minus pi(R-3)^2, because that seems to take the total area, and subtract the smaller circle's area, leaving only the area of the "doughnut" shaped area? Am I missing something obvious, or is the test's given answer wrong? Thank you!
Answer by dabanfield(803) About Me  (Show Source):
You can put this solution on YOUR website!
You are correct. Their answer is the area of the inner circle. :)