The G.C.D of 1.08, 0.36 and 0.9 is

Given numbers are 1.08 , 0.36 and 0.90

 H.C.F of 108, 36 and 90 is 18                  [  $\because$ G.C.D is nothing but H.C.F]

 Therefore, H.C.F of given numbers = 0.18