Most problems in trigonometry involve finding the length of an unknown side of a triangle when given one angle and one side or finding an unknown angle in a triangle when the lengths of two sides are given. The solution procedure is always the same:

• Sketch the triangle.

• Identify the known and unknown quantities and show on the sketch.

• Decide which trigonometric function to use.

• Set up an equation using a trigonometric function.

• Solve the equation for the unknown quantity.

Procedure to solve triangle using trigonometry.

The next examples illustrate how to solve for sides of a triangle using trigonometric functions.

EXAMPLE 20.4A: Solving a Right Triangle

  EXAMPLE 20.4A: Solving a Right Triangle (Continued)