If the 4th, 10th and 16th terms of a G.P. are x, y and z respectively, prove that x, y, z are in G.P.

Given, a 4 = x, a 10 = y and a 16 = z. We know that a n = ar n - 1 ∴ a 4 = ar 3 = x, a 10 = ar 9 = y and a 16 = ar 15 = z. Dividing y by x we get, Dividing z by y we get, Hence, proved that x, y, z are in G.P.