Question

The measure of angle O is 7pi/6. The measure of its reference angle is.... ° and sin O is .....

Answer 1

`(7 \pi )/(6)` is in the 3rd quadrant... (It is also 210 degrees)
To find the reference angle (which is the distance to the x-axis)

`(7 \pi )/(6) - \pi = ( \pi )/(6)` (or 30 degrees)

sin
`( \pi )/(6) = (1)/(2)`