Controlling angle of LineTrace

I am working on a sidescroller shooter, and got the shooting and aiming with a gun down, but i want to be able to throw a grenade in a spesific angle.
That angle i want to be controlled with a LineTrace that get the the angle my right joystick are in.

Been working on this for some time, and as a beginer, i am running out of ideas to pull this off, could someone push me in the right direction?