N ΔABC, if the length of sides a, b, and c are 3.5 centimeters, 5.5 centimeters, and 6 centimeters respectively, what is m∠C to two decimal places?

We are given with three sides with measurements such as below:

a = 3.5 cm

b = 5.5 cm

c = 6 cm

We are asked to solve for m∠C. To solve this we need to apply Law of Cosines such as below:

cos C = a²+b² - c² / 2ab

cos C = 3.5² + 5.5² - 6² / (2*3.5*5.5)

cos C = 0.16883

C = 80.28°