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2006 Cyprus MO/Lyceum/Problem 17

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Problem

AB\Gamma is equilateral triangle of side \alpha and A\Delta=BE=\frac{\alpha}{3}. The measure of the angle \ang \Gamma PE is

\mathrm{(A)}\ 60^\circ\qquad\mathrm{(B)}\ 50^\circ\qquad\mathrm{(C)}\ 40^\circ\qquad\mathrm{(D)}\ 45^\circ\qquad\mathrm{(E)}\...

Solution

Label point F on A\Gamma such that \Gamma F=\frac{\alpha}{3}.

By symmetry we see that the triangle in the middle is equilateral, so the measure of \angle\Gamma PE is 60^{\circ}, and the answer is \mathrm{(A)}.

See also

2006 Cyprus MO, Lyceum (Problems)
Preceded by
Problem 16
Followed by
Problem 18
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