2 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 that result in 30 60 90 or 45 45 90 triangles are used frequently on exercises and tests because their sine and cosine values 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 cose and sine 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 Degrees Radians 0 0 30 I 45 60 90 120