SOLUTION: please help me thank you. solve for the unknown part. 8^2=7^2+14^2-2(7)(14)cosA

Algebra ->  Trigonometry-basics -> SOLUTION: please help me thank you. solve for the unknown part. 8^2=7^2+14^2-2(7)(14)cosA      Log On


   

Question 1085918: please help me thank you. solve for the unknown part. 8^2=7^2+14^2-2(7)(14)cosA
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
+8%5E2+=+7%5E2%2B14%5E2-2%287%29%2814%29cosA+
Solving for A:
+64+=+49+%2B+196+-+196cosA+
+-181+=+-196cosA+
+cosA+=+181%2F196+=+0.923469+
+A+=+cos%5E-1%280.923469%29+=+0.393769+ radians (about 22.561 degrees)