Question

In below fig, OP, OQ, OR and OS arc four rays. Prove that: ∠POQ + ∠QOR + ∠SOR + ∠POS = 360° 

Answer 1

Given that, 

OP, OQ, OR and OS are four rays 

You need to produce any of the ray OP, OQ, OR and OS backwards to a point in the figure. 

Let us produce ray OQ backwards to a point T  so that TOQ is a line Ray OP stands on the TOQ.