Getting the tension(Static equilibirum)

[honestliar]

Homework Statement

A system cord is knotted at point 0. Determine the angle of the force exerted at cord c If the mass of the hanging block is A=850g(8.34N) the tension in B=42N (the angle of Cord B is 25 degrees from the X-axis)

The Image: http://tinypic.com/m/5ani0y/3

Homework Equations

a/sinA = b/sinB = c/sinC

The Attempt at a Solution

8.43/sinA = 42/sinB = c/sin65

so to get the value of c I need to use the cosine law w/c gives me the answer of c=34.544

If i substitute this value in getting the value of sinA it will be sinA=(34.544)(8.34)/Sin65 w/c gives me a wrong answer.

Help please

 

[Winzer]

How about starting off with the sum of the forces for each component?