In angle ABC, AB = 2.5 m, BC = 3.2 m and AC = 2.9 m. Use the Cosine Law to find , to the nearest degree.

9514 1404 393

  ∠A ≈ 72°

Step-by-step explanation:

Fill in the given numbers and do the arithmetic.

  cos A = (2.9² +2.5² -3.2²)/(2(2.9)(2.5)) = 4.42/14.5

The inverse cosine function is used to find the angle, given its cosine.

  A = arccos(4.42/14.5)

  ∠A ≈ 72°

the answer is c: divide the arc's degree measure by 360°, then multiply by the circumference of the circle.