Find the sum to indicated number of terms in each of the geometric progressions in
terms.
Given: √7, √21, 3√7 ,... n terms.
Sum of n terms of a G.P. is given by: 
(a: First term of G.P, r: common difference of G.P, n: Number of terms of the G.P)
First term of the Given G.P (a) = √7
Common difference of the given G.P(r) = 
= √3
Number of terms(n): n
Let the sum of n terms be s
∴ The sum of n terms of the given sequence is:
8