What are the forces at play in Sally's car rescue scenario?

[7282]

Hey, I'm having problems with this questions

Sally’s car is stuck in a snow bank, but she is very knowledgeable about physics. She ties a rope from her car to a tree 25.0 m away and then pulls sideways on the rope at the midpoint. If Sydney applies a force of 425 N and draws the rope over a horizontal distance of 1.50 m, how much force is applied to the car?

I've drawn out a diagram
http://i1289.photobucket.com/albums/b505/homework2012/q2_zps6d9f0975.jpg

How do i begin to solve this?
I think that the triangle formed will be an isosceles triangle so 2 angles are the same with 2 side lengths (T in 1st rope=2 in second rope)

 

[CWatters]

You haven't shown all the forces on your diagram. Let's call the point at which Sally is pulling point S. What are the forces acting at Point S? Well obviously there is the force Sally is applying but there are also two other forces, one for each rope. Since the car isn't moving (yet) the forces are all in balance. Label an angle and look at the components of the various forces.