MathDB
Area in circle c, outside circle a and circle b

Source: 2011 AMC A Problem 18

June 25, 2011
geometryrectangleLaTeXAMC

Problem Statement

Circles A,B,A, B, and CC each have radius 1. Circles AA and BB share one point of tangency. Circle CC has a point of tangency with the midpoint of AB\overline{AB}. What is the area inside Circle CC but outside circle AA and circle BB ?
[asy] pathpen = linewidth(.7); pointpen = black; pair A=(-1,0), B=-A, C=(0,1); fill(arc(C,1,0,180)--arc(A,1,90,0)--arc(B,1,180,90)--cycle, gray(0.5)); D(CR(D("A",A,SW),1)); D(CR(D("B",B,SE),1)); D(CR(D("C",C,N),1));[/asy]
<spanclass=latexbold>(A)</span> 3π2<spanclass=latexbold>(B)</span> π2<spanclass=latexbold>(C)</span> 2<spanclass=latexbold>(D)</span> 3π4<spanclass=latexbold>(E)</span> 1+π2{ <span class='latex-bold'>(A)</span>\ 3 - \frac{\pi}{2} \qquad <span class='latex-bold'>(B)</span>\ \frac{\pi}{2} \qquad <span class='latex-bold'>(C)</span>\ 2 \qquad <span class='latex-bold'>(D)</span>\ \frac{3\pi}{4} \qquad <span class='latex-bold'>(E)</span>\ 1+\frac{\pi}{2}}