Find the Bearing from A to C & Angle B: Solve Here

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SUMMARY

The discussion focuses on calculating the distance and bearing from point A to point C in a geometric problem involving an airplane's flight path. The airplane travels 470 miles from A to B at a bearing of 25 degrees and then 250 miles from B to C at a bearing of 40 degrees. The angle B, which is crucial for applying the law of cosines, is determined to be 165 degrees. The formula used for calculating the distance AC is AC = √(470² + 250² - 2(470)(250)cos(165).

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cbarker1
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Dear everyone,

An airplane flies 470 miles from point $A$ to point $B$ with a bearing of 25 degrees. It then flies from 250 miles from point $B$ to point $C$ with a bearing of 40 degrees. Find the distance and the bearing from A to point C.
Work

Bearing Problem.png

I understand that I need to use law of cosines for the side $b$ which is opposite of the angle $B$. But I have a hard time with find what is the angle $B$ is. I forgot many things from geometry. How to determine the angle from point $A$ to point $C$?

Thanks
Cbarker1
 
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$AC = \sqrt{470^2+250^2 - 2(470)(250)\cos(165)}$

bearing = $25^\circ + m\angle{BAC}$

$\angle{BAC}$ may be found using either the sine or cosine law
 
How did you determine the angle ABC to be 165?
 
bearings.jpg
 

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