1. The problem statement, all variables and given/known data Calculation of the forces C and T in the figure http://www.picpaste.com/20140127_171733-lxIN0kJQ.jpg [Broken] http://www.picpaste.com/20140127_171733-lxIN0kJQ.jpg [Broken] My problem is that I don't understand how cos and sin is given I know the rules SOHCAHTOA 2. Relevant equations Equations used are Sum of Fx= 0 and Sum of Fy = 0 3. The attempt at a solution As this is an example from my coursework material, it is already solved. But I want to understand it there for I will present the solution Sum of Fx = 0 8+Tcos40 + Csin20 - 16 = 0 0,766T+0,342C=8 Sum of Fy = 0 Tsin40-Ccos20-3=0 0,643T-0,940C = 3 By combining the both equations we can solve for C and T Answer is T = 9,09 kn and C = 3,03 kn So basically my question is how are cos and sin given? yeah i know its a triangle and I know of SOH CAH TOA rule.. but i dont seem to grasp it when in this Picture Actually as I am used to see a problem I first draw a triangle for example for the 40 degree one, sometimes i divide a resultant force into two composants I see that T = hypotenuse Then I look at the adjacent side, and normally there is a variable there which is present without a value that I want to be solved.. Now in this problem 8 isnt used as a value. Normally I would divide T into Tx and Ty, and draw to triangles. So how should I look at this problem now? how do i know its sin i will use respectively cos... if someone could explain it It would be very kind of you . how should I Think? B] I Believe in this problem I am not supposed to divide into two composants, but i want to know how they decide "when to use cos resp sin"