Physics homework question! Really weird question, I can't seem to wrap my head around it. Help!!

An alpha-particle collides with an oxygen nucleus which is initially at rest. The alpha-particle is scattered at an angle of 66.0 degrees from its initial direction of motion, and the oxygen nucleus recoils at an angle of 52.0 degrees on the other side of this initial direction. What is the ratio, for alpha-particle to oxygen nucleus, of the final speeds of these particles? The mass of the oxygen nucleus is four times that of the alpha particle.

Question

Physics homework question! Really weird question, I can't seem to wrap my head around it. Help!! 

An alpha-particle collides with an oxygen nucleus which is initially at rest. The alpha-particle is scattered at an angle of 66.0 degrees from its initial direction of motion, and the oxygen nucleus recoils at an angle of 52.0 degrees on the other side of this initial direction. What is the ratio, for alpha-particle to oxygen nucleus, of the final speeds of these particles? The mass of the oxygen nucleus is four times that of the alpha particle.

michele_laino · Answer

hint:
you can solve your problem like an elastic collision between the alpha-particle and the nucleus of Oxygen