Algebra I / Elem. Algebra
Introduction to Algebra Linear Equations and Inequalities Functions and Graphs I Lines and thier Graphs Linear Systems
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Exponents & Polynomials Intermediate Algebra starts here!

Factoring Rational Expressions Rational Equations and Applications
Algebra III / Inter. Algebra
Radical Expressions Nonlinear Equations and Applications Functions and Graphs II Exponential and Logarithmic Functions
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Equations and Inequalitites Functions and Graphs Polynomial and Rational Functions Exponential and Logarithmic Functions Systems and Matrices Geometry Basics Conic Sections Sequences and Series
Trigonometry
The Six Trigonometric Functions Right Triangle Trigonometry Circular Functions Graphs of Trigonometric Functions Trigonometric Identities Trigonometric Equations Oblique Triangles and the Laws Vectors Complex, Parametric, and Polar Forms
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15.Functions of Several Variables
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S = contains supplemental resources
Course: Trigonometry
Topic: Oblique Triangles and the Laws
Subtopic: Law of Sines

Overview

All the trig we have done so far in the course has been "right angle trig" where we required a right triangle before we could set-up and use any of the six trig functions. In this chapter we learn two laws that enable us to use trig functions on oblique (non-right) triangles. The first of these is the law of sines. It is based on ratios of the sine of an angle and the length of the side opposite that angle.

Objectives

By the end of this topic you should know and be prepared to be tested on:

• 7.1.1 Know the law of sines formula
• 7.1.2 Understand that the law of sines can be used in cases when the information given is of the form AAS, ASA, or SSA
• 7.1.3 Solve oblique triangles using the law of sines

Terminology

Define: oblique triangle, included side, law of sines

Memorize the Law of Sines! All variations on the proportions are shown below using standard triangle notation. Note that you can "flip" all three ratios if you need the side variables in the numerator instead.

Supplementary Resources

Need help understanding how to identify AAS, ASA, etc.? Read Help for Oblique Triangles.