It makes the following angle with the negative of the "1" axis (the axis of F1): tan^(-1)(9.6/3.2)=71.56 degrees or 180+71.56 degrees = 251.56 degrees with the positive "1" axis (same thing) It lies in the 3rd quadrant

20. I am assuming you ask here the same question. The answer is :

The opposite equivalent force is found by:

F=sqrt(8.2^2+20.6^2)=22.17N

It
makes the following angle with the negative of the "1" axis (the axis
of F1): tan^(-1)(20.6/8.2)=68.29 degrees or 180+68.29 degrees = 248.29
degrees with the positive "1" axis (same thing). It lies in the 3rd quadrant