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3D Geometery
Posted:
Apr 23, 2005 10:04 PM


Suppose there are two parallel planes P and Q in space. The plane P contains the line l which is parallel to another line l' lying in Q. Suppose further that the line m lies in Q and meets l' at a point P. I'm trying explain why P is the point on m that is closest to l. Clearly the shortest distance between two parallel lines is the perpendicular distance between them. Is there any neat way to show that any line through l', in the plane perpendicular to the plane spanned by l and l' satisfies the above property?



