given that 2nd and the 3rd term of a geometric progression are 18 and 54 find the 5th term

Answer 1

ar = 18
ar^2 = 54

divide the 2nd by the 1st:
ar^2 / ar = 54/18
r = 3

then in ar = 18
3a = 18
a = 6

ar^4 = 6(3^4) = 486

or,

once we had r = 3
and knowing term3 = 54, then
term4 = 54*3 = 162
term5 = 162*3 = 486