Question

How do you find the reference angle in degrees and radians 120 degrees?

Answer 1

The reference angle is the angle between the terminal arm of the angle and the x axis always larger than 0 degrees and smaller than 90 degrees.

Explanation:

Since 120 degrees is in quadrant 2, the reference angle, represented by `theta`, can be found by solving the equation `120 + theta = 180`

`theta = 60`

So, the reference angle is 60 degrees. To convert this to radians, we multiply by the ratio `pi/180`.

`60 xx(pi/180)`

Before we multiply, we can have the 180 eliminate the 60 and become a 3 in the denomiator.

This leaves us with `pi/3` radians, which is our reference angle in radians.

Practice exercises:

1. Find the reference angle, in degrees and in radians, of 40 degrees.

2. Find the reference angle, in degrees and in radians, of 335 degrees.

Good luck!