Answer:
Option B :39 degrees is the correct.
The nearest degree is 39°
Step-by-step explanation:
Laws of cosines relates each side with its opposite angle.
Formula for this is :
[tex]c^{2} =a^{2} +b^{2} - 2abcosC[/tex]
[tex]a^{2} = b^{2}+c^{2} - 2bccosA[/tex]
[tex]b^{2} =a^{2}+c^{2} -2accosB[/tex]
in figure a=28
b=18
c=25
Here we have to find angle between a and c that is B
So [tex]18^{2} = 25^{2} +28^{2} -2*25*28cosB[/tex]
324 = 625 + 784 - 1400cosB
1400cosB = 625 + 784 - 324
1400cosB = 1085
cosB = 0.775
∠B = 39.195° ≈ 39°
The boat change 39° when it made its first turn.
Learn more about Laws of cosines here -https://brainly.ph/question/13424723
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