B. Solving Problems Using the Sine Law

The sine law allows you to solve problems that involve two angles and their opposite side lengths, where one angle or one side is the unknown.

Example 1

Determine the value of x.

It may be helpful to label the triangle with the more familiar variables A, B, C and a, b, c. Make sure to label an angle and the side across from it using the same letter.

The values for A, a, and C are given and c is the unknown, so use the equation .

The value of x is approximately 75.2 m.

A guide to using a TI83/84 calculator for solving equations that include the sine law can be found in the Equipment Room or by clicking here.