On the planet Newtonia, a simple pendulum having a bob with a mass of 1.25KG and a length of 188.4CM takes 1.55S, when released from rest, to swing through an angle of 11.6degrees, where it again has zero speed. The circumference of Newtonia is measured to be 5.15×10^4km. What is the mass of the planet Newtonia?