A very large firecracker explodes in the hallway into 3 fragments. Physics students rush to the scene to enrich their knowledge of the law of conservation of momentum. They report that

Question

A very large firecracker explodes in the hallway into 3 fragments. Physics students rush to the scene to enrich their knowledge of the law of conservation of momentum. They report that 
Fragment 1: mass=1.23kg, v=8.70m/s, north
Fragment 2: mass =2.60kg,v=6.10m/s,east 
fragment 3: ?????

A) calculate the magnitude and direction of the momentum of the 3 fragment. (Keep in mind that momentum is a vector quantity)

b) if the 3rd fragment has a speed of 11.6m/s what is its mass?

Please show all work I would greatly appreciate it Bc I am extemtly lost