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°