MathDB
1994 AMC 12 #29

Source:

December 30, 2011
trigonometryAMC

Problem Statement

Points A,BA, B and CC on a circle of radius rr are situated so that AB=AC,AB>rAB=AC, AB>r, and the length of minor arc BCBC is rr. If angles are measured in radians, then AB/BC=AB/BC= [asy] draw(Circle((0,0), 13)); draw((-13,0)--(12,5)--(12,-5)--cycle); dot((-13,0)); dot((12,5)); dot((12,-5)); label("A", (-13,0), W); label("B", (12,5), NE); label("C", (12,-5), SE); [/asy] <spanclass=latexbold>(A)</span> 12csc14<spanclass=latexbold>(B)</span> 2cos12<spanclass=latexbold>(C)</span> 4sin12<spanclass=latexbold>(D)</span> csc12<spanclass=latexbold>(E)</span> 2sec12 <span class='latex-bold'>(A)</span>\ \frac{1}{2}\csc{\frac{1}{4}} \qquad<span class='latex-bold'>(B)</span>\ 2\cos{\frac{1}{2}} \qquad<span class='latex-bold'>(C)</span>\ 4\sin{\frac{1}{2}} \qquad<span class='latex-bold'>(D)</span>\ \csc{\frac{1}{2}} \qquad<span class='latex-bold'>(E)</span>\ 2\sec{\frac{1}{2}}