What does M have to do with it? is "M
if thats right, then according to the law of cosines
(AB)2=(CB)2+(CA)2-2(CB)*(CA)*(cos(M 2+13 2-2*29*13*cos(41)=440.948976511858
(AB)2=440.948976511858
AB=(440.948976511858)1/2=20.9987851199029607
therefore AB=20.9987851199029607
