Special Right Triangles

In this section we will be calculating the trigonometric ratios of the basic angles of a unit circle. Before we can begin these calculations we need to review the special right triangles. These right triangles include the 30°-60°-90° and 45°-45°-90° triangles. The lengths of the sides of these special triangles always have the same ratios.

The sides of a 45°-45°-90° are always in a ratio of 1 to 1 to .

The sides of a 30°-60°-90° are always in a ratio of 1 to to 2.

Take a moment to become familiar with these triangles. You will need these values to find the trigonometric functions on the unit circle.