Why is it that sin 5π6=12, but sin−1126=5π6? will give extra points for correct answer

Fredrick designed an experiment in which he spun a spinner 20 times and recorded the results of each spin

Determine whether the quadrilateral below is a parallelogram. justify/explain your answer (this means back it up! give specific information that supports your decision. writing just "yes" or "no" will result in no credit.)

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.