Answer:
30 cm.
Step-by-step explanation:
Draw a line from R perpendicular to PQ to meet PQ at T.
RQT forms a right-angled triangle with RT = SP = 15.
So tan 36.87 = RT / TQ
tan 36.87 = 15 / TQ
TQ = 15 / tan 36.87
= 20 cm.
Now PT = SR = 10, so
PQ = 10 + 20
= 30 cm.