Three planets, Hctim of mass 4.88 x 1024 kg, Yzeerg of mass 3.18 x 1023 kg, and Yrral of mass...

Three planets, Hctim of mass 4.88 x 1024 kg, Yzeerg of mass 3.18 x 1023 kg, and Yrral of mass 5.98 x 1024 kg in the solar system Sraggeb are in harmonic convergence (i.e. they are perfectly aligned). See diagram. At the exact time that they are aligned, calculate the net force acting on planet Yzeerg.