If p,q be two A.M.'s and G be one G.M. between two numbers, then G2=
(b) (2p - q)(2q - p)
Let the two numbers be a and b
a, p, q and b are in A.P>
∴p−a=q−p=b−q
⇒p−q=q−p and q−p=b−q
⇒a=2p−q and b=2q−p ..... (i)
Also, a, G and b are in G.P.
∴G2=ab
⇒G2=(2p−q)(2q−p)