Question

Find the 4 term of a geometric series whose second and fifth terms are respectively 6 and 162 .​

Answer 1

The GP can be written as a, ar, ar², ar³, ar⁴, ....

Given the second term = ar = 6

and the 5th term = ar⁴ = 162

So ar⁴/ar = 162/6

ie, r³ = 27

r = ∛27 = 3

So the 4th term = ar³ = ar*r² = 6*3² = 6*9 = 54