Let X be a point in the interior of triangle PQR.
Let a line through X intersect rays QP and QR in points A and B respectively.
Let Y be the point on line segment AB such that |BY| = |AX|.

Prove that |AB| is a minimum if and only if AB is perpendicular to QY.

(In reply to minimum? by Dej Mar)

|AB| means the measure or length of line segment AB. Since the length of AB varies depending on the position of X, Bractals is asking us to prove that |AB| reaches its minimum value (i.e., segment AB has its minimum length for any position of X) iff angle QYA is a right-angle.

:-)

Posted by JayDeeKay on 2007-05-10 09:03:18