MathDB
PT is perpendicular to XY

Source: Iran TST 2005

April 20, 2005
geometrycircumcircleratioparallelogramsymmetrygeometric transformationreflection

Problem Statement

Assume ABCABC is an isosceles triangle that AB=ACAB=AC Suppose PP is a point on extension of side BCBC. XX and YY are points on ABAB and ACAC that: PXAC , PYABPX || AC \ , \ PY ||AB Also TT is midpoint of arc BCBC. Prove that PTXYPT \perp XY