The fifth term of a G.P. is 81 and its second term is 24. Find the geometric progression.
Use your definitions:
the fifth term of a g.p. is 81 ---> ar4=81
second term is 24 -----> ar = 24
divide them:
ar4ar = 8124
r3 =278
r = 32
then in ar=24
(3/2)a = 24
a = 16
the GP is
16, 24, 36, 54, 81, ...