Resultant force from three forces.

[Colts]

Homework Statement

http://session.masteringengineering.com/problemAsset/1127110/6/Probs.2-39_40.jpg
I will refer to this picture for the problem.
I have to find the resultant of the three force vectors. I know all except F1 and theta. I am given it for this problem to find the resultant. F1=510N and theta=20 degrees.

Homework Equations

Each theta is the degrees from positive x axis.
Fx1cos(theta1)+Fx2cos(theta2)+Fx3cos(theta3)=x
Fy1sin(theta1)+Fy2sin(theta2)+Fy3sin(theta3)=y
sqrt(x^2+y^2)=answer

The Attempt at a Solution

510cos(70)+600cos(150)+400cos(30)=1.22
510sin(70)+600sin(150)+400sin(30)=979.24
sqrt(1.22^2+979.24^2)=979.24

 

[Redbelly98]

Welcome to Physics Forums.

For the 600 N force, the angle is not 150°. Look carefully at the figure again.

 

[Colts]

The angle for 600N should be 4/5 for the x direction and 3/5 for the y direction. Now how do I find the angle? Thats the next part.

Edit: Nevermind. I got it. Thank you