Resultants of Nonconcurrent Force Systems

[JordanIV]

The question is to determine the magnitude, direction and sense of the resultant force of the nonconcurrent force system. Locate the resultant with respect to point O.

I've looked at example in the book and tried to follow this problem as close to it as possible.

(1)I first tried to find the x and y components of the forces. Since I'm finding the x component, it will be cosine. I set it up as 15cos75-25(12/13) but am not sure if that's correct. Also Correct me if I'm wrong with my signs. I then found the y value, but I'm still not sure if I have set it up correctly or have any of the signs right for the the 10, 15 and 25. Correct me if I'm wrong.

(2) I then used a^2+b^2=c^2. I did -5.73^2+15.75^2=square root of 280.89=16.76

(3) I don't know what its called but its a symbol of an 'x' with a line above it equals the inverse tangent of the y and x component. So i took the inverse tangent of the y component over the x component. As you can see i did the inverse tangent of 15.75/-5.73=-70.71.

(4)The example in the book did not use either of the 4 numbers pictured(8',6',5',4'). So I assumed that it was not used in this problem.

 

[member 553083]

This is the answer I got. The magnitude is 16.76N, direction is -70.71 degrees, and the sense is counterclockwise with respect to point O.Is this answer correct? If not, can you show me how to do it correctly?