Question

Which quadrant contains - 11n/18 and what is the reference angle?

Answer 1

option B: III , 7pi/18

Explanation:

Given angle is
`(-11\pi)/(18)`

Given angle is negative , so we add 2pi

`(-11\pi)/(18)+2\pi`

Take common denominator 18

`(-11\pi+36\pi)/(18)`

`(25\pi)/(18)`

pi is 180 degree. Lets find degree for this radians

25 * 180 / 18 = 250 degree

250 degree lies in third quadrant (III)

Now we find reference angle

to find the reference angle for the angle in third quadrant we subtract 180

250 - 180 = 70 degree

now convert it into radians

`70 * (\pi )/(180) =(7\pi )/(18)`