Trigonometry with Oblique Triangles

Cosine Law

To use the sine laws introduced last section, we need to know at least one complete side length to angle ratio including another known side length or angle. Sometimes we may not have that information, but instead you’re given all three side lengths and no angle. In this case, we…

Sine Law

Thus far, we’ve learned how to efficiently solve right triangles using trigonometric functions. Remember that to “solve” a triangle means we’re finding all its unknown lengths and angles. What if we have a triangle that is not a right-angle triangle (called an oblique triangle)? If your oblique triangle has the following configurations:…

CAST Rule and Reference Angles

Given the right triangle shown below, a summary of all the trigonometric functions we’ve learned so far are listed: Trigonometric Functions: null Reciprocal Trigonometric Functions: null Inverse Trigonometric Functions: null Inverse Reciprocal Trigonometric Functions: null In the last unit, we explored all six of these trigonometric functions using angles found…