MathDB
Possible perimeters

Source:

May 11, 2006
geometryperimeterinequalitiestrigonometryperpendicular bisectorPythagorean Theorem

Problem Statement

Point BB is on AC\overline{AC} with AB=9AB = 9 and BC=21BC = 21. Point DD is not on AC\overline{AC} so that AD=CDAD = CD, and ADAD and BDBD are integers. Let ss be the sum of all possible perimeters of ACD\triangle ACD. Find ss.