In ΔSTU, s = 6.1 cm, t = 3.2 cm and u=7.4 cm. Find the measure of ∠S to the nearest 10th of a degree.
We can use the Law of Cosines to solve this
(6.1^2 - 3.2^2 - 7.4^2) / (-2 * 3.2 * 7.4) = cos S
To find S we have that
arccos [ (6.1^2 - 3.2^2 - 7.4^2) / (-2 * 3.2 * 7.4) ] = S ≈ 54.1°
