Question

Use the Law of Cosines to find the missing angle. In triangle FGH, HF = 16 ft, FG = 23 ft, and m∠F = 52°. Find the measure of f. Round your answer to the nearest whole number.

Answer 1

F = 18 ft.

The law of cosines states 
c² = a² + b² - 2ab cos C

Using our information, we have 
c² = 23² + 16² - 2(23)(16)cos 52
c² = 529 + 256 - 736cos 52
c² = 785 - 736cos 52
c² = 331.8732

Taking the square root of both sides, we have
c = √331.8732 = 18.22 ≈ 18