MathDB
P05 [Geometry] - Turkish NMO 1st Round - 2014

Source:

May 21, 2014
geometry

Problem Statement

Let DD be a point on side [BC][BC] of ABC\triangle ABC such that AB=AC|AB|=|AC|, BD=6|BD|=6 and DC=10|DC|=10. If the incircles of ABD\triangle ABD and ADC\triangle ADC touch side [AD][AD] at EE and FF, respectively, what isEF|EF|?
<spanclass=latexbold>(A)</span> 12<spanclass=latexbold>(B)</span> 23<spanclass=latexbold>(C)</span> 1<spanclass=latexbold>(D)</span> 98<spanclass=latexbold>(E)</span> 2 <span class='latex-bold'>(A)</span>\ \dfrac{1}{\sqrt{2}} \qquad<span class='latex-bold'>(B)</span>\ \dfrac{2}{\sqrt{3}} \qquad<span class='latex-bold'>(C)</span>\ 1 \qquad<span class='latex-bold'>(D)</span>\ \dfrac{9}{8} \qquad<span class='latex-bold'>(E)</span>\ 2