Calculating Acceleration of a 2.60 kg Object with Given Tensions and Angle

[crazy_nuttie]

Homework Statement

The tensions of the ropes acting on a 2.60 kg object are shown. Find the value of ax, the x-component of the acceleration, if T1=1.40 N, T2=2.80 N, T3=3.20 N, T4=4.70 N, and θ=12.0°? Diagram:
http://img19.imageshack.us/img19/3733/knpic0506bnew.png

Homework Equations

F netx = m * a
a = F netx / m

The Attempt at a Solution

Well, I added the two forces in the X direction simply by doing:

T1 * Cos θ - T3 = m*a

a = ( T1*Cos θ - T3 )/ a

However, I keep getting the wrong answer. Can anyone help me out? Thanks

 

[Doc Al]

The Attempt at a Solution

Well, I added the two forces in the X direction simply by doing:

Looks like three of those forces have x-components. What about T₄?