### Home > INT3 > Chapter 9 > Lesson 9.1.5 > Problem 9-66

9-66.

Calculate each of the following values. Express your answers both exactly and as decimal approximations.

Draw a unit circle and locate

radians. Remember that a full circle as

radians and a half circle has radians. How many degrees is equivalent to

radians? Draw a right triangle and use the special triangle relationship to find the exact value.

or

Since

is equivalent to , of is .

What isof ? Locate on the unit circle. Draw a right triangle.

Notice thatis your reference angle.

Use therelationship to find the exact value.