5 distinct two digit no are in gp find the middle term

Let the numbers be a, ar, ar^2, ar^3, ar^4,

Since all are 2 digit number r = 2 3 or 3 2 (as fourth power of integers greater than 3 are 3 digit numbers) Hence the five numbers are (16, 24, 36, 54, 81) Hence middle term is 36.