Hi!

We start with step 5.

First some nomenclature.

Let the point where three forces meet is "O".

Let the point where you have written 3N be A.

Mark a point B on line AO such that A and B are on opposite sides of O.

Mark a point C on the light line going upwards(line adjacent to dark line of 9N)

Mark a point D on OC such that C and D are on oppsite sides of O.

Let 3N force be the third force.(since you have drawn coordinate axes along that force)

Now we resolve 9N force.

If you resolve this force along the co-ordinate axes, you will see that one component will be in the direction of OB and other in the direction of OC.

We require the component in the direction OB.

Now, the force vector of 9N force makes 96deg. angle with OA.

Hence it makes 84deg. angle with OB. So, its component along OB is 9N*cos(84deg.)

Now we resolve 8.1N force.

This force will be resolved along OB and OD.

The angle here is 76deg.(160-84 or 180-104). Hence component is 8.1N*cos(76deg.)

Keep Smiling

Malay