Hi, I hope this type of question is against the rules here. But I have a slight emergency. I have to substitute teach a HS physics class tomorrow. I am a biology teacher, so this is out of my realm. I have to explain a couple problems and have no idea how to begin. I am figuring I need to sin and cos some angles, but the rest is unknown. Here's the question, if anyone can step me through the math of this, I will be forever grateful A force board is set up in a physics lab and the three spring scales are hooked to the central ring and the notched perimeter of the table. The first scale reads 12.5 N at an angle of 0 degrees. The second scale reads 17.3 N at an angle of -34 degrees. If the three forces are balanced, what are the reading and angle of the third spring scale?