Range of two balls are R1=gu2sin2θ1=R2=gu2sin2θ2.
Now, maximum height by both balls are h1=2gu2sin2θ1 andh2=2gu2cos2θ2
∴h1h2=(2gu2sin2θ)(2gu2cos2θ)=2gu2sinθcosθ=4R
⇒R=4h1h2
Hence, both A and R are true and R is the correct explanation of A.