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3D loci of points

Source: Czech and Slovak Olympiad 1958, National Round, Problem 4

June 13, 2024
Locusgeometry3D geometry

Problem Statement

Consider positive numbers d,vd,v such that d>vd>v. Moreover, consider two perpendicular skew lines p,qp,q of distance vv (that is direction vectors of both lines are orthogonal and minXp,YqXY=v\min_{X\in p,Y\in q}XY = v). Finally, consider all line segments PQPQ such that Pp,Qq,PQ=dP\in p, Q\in q, PQ=d. a) Find the locus of all points PP. b) Find the locus of all midpoints of segments PQPQ.