Question

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

Answer 1

Answer:

option B:  III   ,  7pi/18

Step-by-step explanation:

Given angle is $\frac{-11\pi}{18}$

Given angle is negative , so we add 2pi

$\frac{-11\pi}{18}+2\pi$

Take common denominator 18

$\frac{-11\pi+36\pi}{18}$

$\frac{25\pi}{18}$

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

$70 * \frac{\pi }{180} =\frac{7\pi }{18}$