In ΔABC, m<C = 38°, a = 12 and b = 14. Find the length of side c, to the nearest integer.

Question

 trigonometry  law of cosines

Answer 1

c^2=a^2+b^2-2abcosC

c^2=12^2+14^2-2(12)(14)(cos38º)

c^2=144+196-336(0.7880107536)

c^2=144+196-264.7716

c^2=340-264.7716

c^2=75.2284

c=√75.2284

c=8.6734307

c=9 units to the nearest integer

Answer 2

Wait a minute!  You have exactly the data that you need to substitute into the Law of Cosines.  You can do this!

Just be sure that your calculator is in degree mode.