Question

Some and cosine?

Answer 1

The measurements of triangle are a = 6.5, b = 7.5 and c = 6

Use law of cosines

cos C = (a² + b² - c²)/2ab

         = [(6.5)² + (7.5)² - (6)²)/2(6.5)(7.5)

        = [42.25 + 56.25 - 36]/97.5

        = 62.5/97.5

        = 0.6410

C = cos^-1 (0.6410)

C = 50.13°

Option 1 is correct .