Hey! I just started study landsurveying and got a task i dont figure out how to get the right answer. My goal is to find the lenght of one of the sides in a triangle, but i can not use pytagoras formula. Here is the formula i am supposed to use (dont care about the text, its norwegian): http://i60.tinypic.com/nejknn.jpg And here is the task: "side a: 50,5845 gon (alfa), in degrees this is 45 side b: 1604,170m (gamma) side c: 1128,620 m (beta) Find the length of side a." I know the answer is 1144,700m. When i have tried i have found b2 and c2, then added those. After that i took b*2, multiplied with c. Then i took the answer from b2 and c2 added together and minus the answer from b*2 multiplied with c, and in the end i multiplied the cosinus of alfa. Im from Norway and my english is not that good, but i hope that someone could help me out, or tell me what i've done wrong.