Which equation could be used to solve for the measure of angle O?
Circle N is shown with a quadrilateral OPQR inscribed inside it. Angle O is labeled x degrees. Angle P is labeled y degrees. Angle Q is labeled z degrees. Angle R is labeled w degrees.
In any quadrilateral where the vertices are on the circumference of a circle, the opposite angles add up to 180 degrees. So, in this case: angle x + angle z = 180
