MathDB
Turkey NMO 2000 1st Round - P19 (Combinatorics)

Source:

July 25, 2012
probabilitygeometryarea of a triangleHeron's formula

Problem Statement

Let PP be an arbitrary point inside ABC\triangle ABC with sides 3,7,83,7,8. What is the probability that the distance of PP to at least one vertices of the triangle is less than 11?
<spanclass=latexbold>(A)</span> π362<spanclass=latexbold>(B)</span> π363<spanclass=latexbold>(C)</span> π36<spanclass=latexbold>(D)</span> 12<spanclass=latexbold>(E)</span> 34 <span class='latex-bold'>(A)</span>\ \frac{\pi}{36}\sqrt 2 \qquad<span class='latex-bold'>(B)</span>\ \frac{\pi}{36}\sqrt 3 \qquad<span class='latex-bold'>(C)</span>\ \frac{\pi}{36} \qquad<span class='latex-bold'>(D)</span>\ \frac12 \qquad<span class='latex-bold'>(E)</span>\ \frac 34