Alex drew a circle with right triangle PRQ inscribed in it, as shown below:

The figure shows a circle with points P, Q, and R on it forming an inscribed triangle. Side PQ is a chord through the center, and angle R is a right angle. Arc QR measures 80 degrees.

If the measure of arc QR is 80°, what is the measure of angle PQR?

50°
40°
80°
70°