MathDB
Equilateral triangle inscribed in a circle

Source: 1959 AHSME Problem 21

August 13, 2013
geometryperimeterratioLaTeXAMCcircleAMC 12

Problem Statement

If pp is the perimeter of an equilateral triangle inscribed in a circle, the area of the circle is: <spanclass=latexbold>(A)</span> πp23<spanclass=latexbold>(B)</span> πp29<spanclass=latexbold>(C)</span> πp227<spanclass=latexbold>(D)</span> πp281<spanclass=latexbold>(E)</span> πp2327 <span class='latex-bold'>(A)</span>\ \frac{\pi p^2}{3} \qquad<span class='latex-bold'>(B)</span>\ \frac{\pi p^2}{9}\qquad<span class='latex-bold'>(C)</span>\ \frac{\pi p^2}{27}\qquad<span class='latex-bold'>(D)</span>\ \frac{\pi p^2}{81} \qquad<span class='latex-bold'>(E)</span>\ \frac{\pi p^2 \sqrt3}{27}