Reference Angle Chart (Page 3 of 5) in pdf

Reference Angle Chart Page 3

A useful thing about reference angles…

The Reference Angle Theorem

A trigonometric function of an angle and its reference angle differ at most in

sign.

Use your calculator to first evaluate each of the following and then to find the reference

angle for each. Write trig functions to three decimals and the reference angle in DMS.

Ref Angle

sin

csc

cot

15 25 ' 37 ''

164 34 '23''

195 25 ' 37 ''

344 34 '23''

Now restate the reference angle theorem in your own words.

We can use the reference angle theorem and all the values that you have memorized to

find the exact value of a lot of different angles.

sin

cos

Quadrant

150

210

120

300

225

315

It’s important to instantly recognize the angles between 0 and 360 that have the key

reference angles 30 , 45 , and 60 . List them below:

QII

QIII

QIV

Because you have memorized the sine, cosine, and tangent of each of those specific

reference angles, you’ve also memorized the sine, cosine, and tangent of each angle you

just listed in that table; you just need to realize it.

Reference Angle Chart Page 3