Jika suku pertama suatu barisan geometri 16 dan suku ketiga 36 ,hitunglah besar suku ke lima !?

u1 = a = 16
u3 = ar^2 = 36

rasionya = ar^2/a = 36/16
r^2 = 9/4
r = √(9/4)
r = 3/2

u5 = ar^4
16 × (3/2)^4
16 × 81/16
=81