My question is

How do I calculate the resultant force if I have two forces one heading 3N and the other 4N. Tha angle between the line that is 3N and the resultant force is 30 degrees and the other one which is the 4N is 60 degrees

How do I calculate the vector

Can someone please provide me an explanation for this as simply as possible

thanks

I am unclear on the picture, but it is clear you have on the triangle two sides, and three angles (remember that the sum inside the triangle is 180). In the case of the angles, make certain you figure out what the INSIDE triangle angles are. Once you have the inside triangles, you can use the law of sines (or cosines) to figure the last side.

a/sinA = b/sinB= c/sinC
http://hyperphysics.phy-astr.gsu.edu/hbase/lsin.html