Oblique Triangles: Law of Cosines
The law of cosines relates the lengths of its sides to the cosine of one of its angles.
Referencing the above
figure, the law of cosines may be written as:
The law of cosines should be used when:
The law of cosines should be used when:
- Seeking length of third side upon knolwedge of two remaining sides and included angle
- Seeking any angle upon knolwedge of all three sides
Example:
For a = 5, b = 6, and γ = 30o in figure below, determine remaining side c.
For a = 5, b = 6, and γ = 30o in figure below, determine remaining side c.
Solution:
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