Solving for Distance using Law of Cosines

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SUMMARY

The discussion centers on solving a navigation problem involving a ship's course adjustment using the Law of Cosines and Law of Sines. The ship initially travels 50 miles from point A to B, then changes its bearing to 62° and 115° at points A and C, respectively. The user initially struggled with applying the Law of Cosines but successfully utilized the Law of Sines to find the necessary distances. The conclusion emphasizes the importance of understanding both laws in solving triangle-related problems in navigation.

PREREQUISITES
  • Understanding of the Law of Cosines for triangle calculations
  • Familiarity with the Law of Sines for angle-side relationships
  • Basic knowledge of navigation bearings and angles
  • Ability to solve trigonometric equations
NEXT STEPS
  • Study the application of the Law of Cosines in navigation scenarios
  • Learn advanced trigonometric identities and their practical uses
  • Explore real-world navigation problems involving multiple course changes
  • Investigate the use of software tools for solving trigonometric equations
USEFUL FOR

Students in mathematics or navigation courses, maritime professionals, and anyone interested in applying trigonometry to real-world navigation problems.

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Homework Statement


A ship sailing due east in the North Atlantic has been warned to change course to avoid a group of icebergs. The captain turns at point A and sails on a bearing of 62° for a while, then changes course again at point C to a bearing of 115° until the ship reaches its original course at point B. The distance between point A and B is 50 miles. How much farther did the ship have to travel to avoid the icebergs?

Homework Equations


a2 = b2 + c2 - 2bc*cosA
b2 = a2 + c2 - 2ac*cosB
c2 = a2 + b2 - 2ab*cosC

a/sinA = b/sinB = c/sin C

The Attempt at a Solution


I figured out all of the angles, but I only have one side, and I can't get the numbers to work in any of the law of cosines equations. I don't know if I should try law of sines, because my professor told me not to use law of sines with any angles greater than 90°. I think making a system of equations in this problem would be too complicated, I'm sure there's an easier way somewhere. Help please?
 

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Oh! Nevermind, law of sines worked just fine. My professor is a poopyhead!
 

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