For first projectile motion, the angle from horizontal is given as,
θ1=30∘
For second projectile motion, the angle from horizontal is given as,
θ2=90∘−30∘
=60∘
The range R1 is given as,
R1=u2sin2θg
=u2sin(2×30∘)g
=√3u22g
The range R2 is given as,
R2=u2sin2θg
=u2sin(2×60∘)g
=√3u22g
Thus, the relation between R1 and R2 is R1=R2.