MathCastle
GeometrySuperchallengePoints, Lines & Planes

Points, Lines & Planes · Superchallenge problem

Five points AA, BB, CC, DD, EE lie on a line in that order. The ten distances between pairs of these points are 33, 44, 55, 77, 88, 99, 1212, 1616, 1919, and kk (listed without regard to which pair gives which). Find kk.