Find tension with two cables at different angles

[gmuck]

Homework Statement

A weight of 5000 N is suspended by two cables. The object is at rest. The first cable is horizontal and the second makes an angle of 143 ° with the first cable. Find the tension of the first cable.

Homework Equations

Erm...I know it's something with sin or cosin.

The Attempt at a Solution

My teacher hasn't given us any equations that have to do with tension, so I am completely and utterly lost. Any help would be greatly appreciated!
It's multiple choice and the possible answers are
4000 N
6640 N
8310 N
3340 N

 

[U.Renko]

if the object is at rest, then accelersation is zero.
if accelaration is zero, then the net force is zero.

 

[Cipherflak]

The tension is just the force exerted by the cables.

Have you made a drawing and applied the three forces working?

 

[MrNerd]

Indeed, there is some sin or cos involved. As mentioned above, the acceleration is zero. What does this imply about the vertical part of the tension?

 

[Cipherflak]

if you break the problem into a horizontal and a vertical part, the sum of forces should be 0 in each of these.

in the horisontal, the force on cable 1 must be equal to the HORIZONTAL PART of the force of cable 2.

In the vertical the VERTICAL PART of cable 2 must balance gravity.

Agree?