Given that P=Q=R. If P+Q=R, then the angle between P and R is θ1. If P+Q+R=0, then the angle between P and R is θ2. What is the relation between θ1 and θ2?

P+Q=R and P=Q=RR=P2+Q2+2PQcosθSubstituting P=Q=R, we get θ=120°If P=Q, then R will pass through the centre of P and Q. Hence, angle between P and R will beθ1=θ2=60°In the second condition, given that P=Q=R and P+Q+R=0. Then, angle between P and R will be θ2=120°θ1=θ22