Vector

that's the formula to find the resultant of a vector if the angle / teta is no 90 deegre

In vector we know Sin and Cos
sin = y/r
cos= x/r

hypotenus = R
opposite = Y
adjacent = X

when we want to find the X or Y of vector and it use x/r it use Cos and if it's using y/r it use Sin
This is the list of Cos and Sin that we can use to :

this is an example question :
1. There are 3 vector the first one go to north west with 15N 37 deegre the aspect of south. The secondone go to south east with 9N 37 deegre the aspect of south and the third one with 10N go to east find the resultan of the vector
we can directly minus f1 and f2 becuase they have same teta or deegre 15-9=6N
F3x+F1x=9-3.6=5.4
F3y+F1y=0+4.8=4.8

√5.4^2 +4.8^2 =7.2N
4.8/5.4= 0.8
tan^-1 0.8 =38,65