Solving 3D Statics Problem with 800N Lamp

[believe14142]

Homework Statement

Three cables are used to support a lamp that weighs 800N. Determine the force in each supporting cable when everything is at equilibrium.

Homework Equations

ƩF in the x-axis = 0
ƩF in the y-axis = 0
ƩF in the z-axis = 0

The Attempt at a Solution

I really don't know how to start this problem. I get the concept of breaking up the components and adding all the forces up in each axis. But what throws me off about this problem is that it isn't centered at the origin. How am I supposed to find the angles of the forces with respect to an axis if the force isn't coming out of the origin?https://mail-attachment.googleusercontent.com/attachment/u/0/?ui=2&ik=dbdf3b9707&view=att&th=13a219c1fc5c23ec&attid=0.1&disp=inline&realattid=f_h7t12d950&safe=1&zw&saduie=AG9B_P-8Wo1xJnmuljT9i03--InW&sadet=1349183678622&sads=Kf9SObn1yzuJjVHHS6SmBxLnTK0&sadssc=1

 

[LawrenceC]

A sketch of the situation would be helpful.

 

[believe14142]

Oh pffft nevermind. I just realized that you can move the forces over so that everything is at the origin.