Let ABC be a triangle with angleA<60°.Let X and Y be the points on the sides AB and AC,respectively,such that CA+AX=CB+BX and BA+AY=BC+CY.Let P be the point in the plane such that the lines PX and PY are perpendicular to AB and AC,pespectively.Prove that angleBPC<120°
發表於 5-6-2008 20:30:37
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