9514 1404 393
Answer:
42°
Step-by-step explanation:
The measure of angle PUR is half the sum of the measures of arcs PR and ST.
∠PUR = (1/2)(arc PR +arc ST)
Using measures in degrees, we have ...
81 = (1/2)(PR +120)
162 = PR +120 . . . . . . multiply by 2
162 -120 = PR = 42 . . . . subtract 120
The measure of arc PR is 42°.