Question

A ship travels due west for 83 miles . It then travels in northwest direction for 111 miles and ends up 165 miles from its original position. To the nearest tenth of a degree how many degrees north of west did it turn when it changed direction? Show your work.

Answer 1

*see attachment for the diagram of the information given

Answer:

115.8°

Explanation:

Due west = 83 miles

Northwest = 111 miles

Distance to its original position = 165 miles

Let x represent the degree north of west that it turned when it changed direction which is the opposite angle of 165 miles.

Thus, to find x, we'd apply the Law of Cosine which is given as:

c² = a² + b² - 2ab*cos C

Where,

C = x

a = 83 miles

b = 111 miles

c = 165 miles

Plug in the values

165² = 83² + 111² - 2*83*111*Cos x

27,225 = 19,210 - 18,426*Cos x

27,225 - 19,210 = - 18,426*Cos x

8,015 = -18,426*Cos x

8,015 = -18,426*Cos x

8,015/-18,426 = Cos x

-0.434983176 = Cos Cmx

Cos x = -0.434983176

x = cos^{-1}(-0.434983176)

x = 115.784223°

x = 115.8°