College Algebra & Trigonometry, 2018a

Chapter 11
The Law of Sines
The Law of Cosines
In Chapter 1, we used the fundamental trigonometric relationships in right triangles
to find unknown distances and angles. Unfortunately, in many problemsolving
situations, it is inconvenient to use right triangle relationships. Therefore,
from the right triangle relationships, we can derive relationships that can be used
in any triangle.
11.1 The Law of Sines
The Law of Sines is based on right triangle relationships that can be created with
the height of a triangle. Often, in this type of a problem, the angles are labeled
with capital letters and their corresponding sides are labeled with lower case
letters.
C
b
a
A
c
B
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