Question

in a triangle ABC, C=10CM A=12CM ANGLE B Is 20 DEGREEZ calculate the lenght of side b

Answer 1

The Law of Cosines:

CosB = (a^2 + c^2 - b^2) / 2ac,
0.9397 = ((12)^2 +(10)^2 - b^2) / 240,
0.9397 = (144 + 100 - b^2) / 240,
0.9397 = (244 - b^2) / 240,
244 - b^2 = 225.53,
-b^2 = 225.53 - 244 = -18.47,
b = 4.3.