Sections:

Law of Sines and Law of Cosines, Page 4

Law of Sines: Examples (continued)

Example 2:

Given angle A = 42 degrees, angle C = 75 degrees and a = 15, solve triangle ABC (round your answer to the nearest tenth).

5.2.4 graphic 1

the measure of angle B = 180 - (42 + 75) = 63 degrees

To find c:

c/sin(75) = 15/sin(42); c sin(42) = 15sin(75); c = 15sin(75)/sin(42); so c = 21.7

To find b:

b/sin(63) = 15/sin(42); b sin(42) = 15sin(63); b = 15sin(63)/sin(42); so b = 20.0