Alevel Further Maths Mechanics question: HELP!!!!!!!

A particle P of mass 6 kg lies on the surface of a smooth plane. The plane is inclined at an angle of 30° to the horizontal. The particle is held in equilibrium by a force of magnitude 49*N, acting at an angle (x) to the plane. The force acts in a vertical plane through a line of greatest slope of the plane.

(a) Show that cos (x) = 3/5


There are other parts to this question, but I think Iwill manage to do them, it's the first part that I really cannot do for some reasons. Can anyone help???
I tried so many times and I could not go anywhere! How do I show that that's the angle??
Any hints will be immensely appreciated!!!!! Thank you!!

Resolve forces parallel to the plane. The forces acting on the particle are its weight and the vertical force of 49N. The angle between this force and the plane is x degrees.

You will need to use g = 9.8, m = 6, and sin(30) = 1/2.