### Home > A2C > Chapter 8 > Lesson 8.1.6 > Problem 8-93

You have seen that you can calculate values of the sine function using right triangles formed by a radius of the unit circle. Values of *θ* that result in 30° − 60° − 90° or 45° − 45° − 90° triangles are used frequently on exercises and tests because their sines and cosines can be found exactly, without using a calculator. You should learn to recognize these values quickly and easily. The same is true for values of cos*θ* and sin*θ* that correspond to the *x*- and *y*-intercepts of the unit circle.

The central angles that correspond to these “special” values of *x* are 30°, 45°, 60°, 90°, 120°, 135°, 150°, 180°, 210°, 225°, 240°, 270°, 300°, 315°, and 330°. What these angles have in common is that they are all multiples of 30° or 45°, and some of them are also multiples of 60° or 90°.

Copy and complete a table like the one below for all special angles between 0° and 360°. Homework Help ✎

Degrees | 0 | 30 | 45 | 60 | 90 | 120 | ||

Radians | 0 |

All of the 'special' values of x are multiples of either 30° or 45°.

Knowing just these two values allows you to easily find the rest.