Question

consider a massless cord attached at both ends to hooks in a ceiling. A 20 kg mass is then suspended from the first cord by a second cors. The angles made by the cord with the ceiling are 40 degrees (left angle) and 25 degrees (right angle). Find the tension in each cord.

I couldn't find the correct equation for this problem.

You have to think it out. First, 20g weight is hanging down. The sum of the forces up and down is zero.

Tleft*sinThetaleft + Tensionright*sinThetaright = mg

Now, the sum of the horizontal forces is zero.

Tensionleft*costhetaleft=tensionright*costhetaright.