Quadrilateral OPQR is inscribed inside a circle as shown below. What equation would be needed to solve for angle P? What is the measure of angle P? You must show all work and calculations to receive credit.

Question

anonymous · Answer

The opposite angles of a cyclic quadrilateral add up to 180. 
A cyclic quadrilateral is a quadrilateral with the four vertices on a circle.

anonymous · Answer

angle P + angle R = 180
angle O + angle Q = 180

Here they are only interested in R and so the first equation will be sufficient to solve for R.