Reference Angle Chart (Page 4 of 5) in pdf

Reference Angle Chart Page 4

Now that we have an understanding of reference angles we can work backwards to find

the answers to all sorts of questions. Most notably, we can find angles from certain given

information.

Let’s start by writing down those formulas for reference angles that I told you you’re

better off not memorizing (did I lie? Oops…). Then we’ll solve them for

rather than

Quadrant

Solved for

III

We’ll need those.

Here’s a little fact you might not know (nor do you really have any reason to know it

before this…):

Getting Reference Angles on Calculators

If you use the inverse functions on your calculator with the absolute value

of any given trig ratio, the calculator always returns the reference angle!

That’s a big deal. If you don’t use the absolute value you are (potentially) entering a

world of pain.

Find the angle/angles between 0 and 360 in the indicated quadrant satisfying the given

information.

Ratio

Quadrant

Reference Angle

Angle(s)

sin

0.5388

sin

0.5388

cos

0.5736

III

tan

1.8041

sec

3.9939

cot

2.3559

sin

.4578

???

cos

.6582

???

Reference Angle Chart Page 4