The power of 100 of lg3 = 100lg3=47.7 1, so the power of 100 of 3 is 48 digits.

Find the law, 1 power unit is 3, 2 power unit is 9, 3 power unit is 7, 4 power unit is 1, 5 power unit is 3, 6 power unit is 9. ...

With a period of 4, the units are 3, 9, 7, 1 respectively.

100 power has exactly 25 cycles, and the unit is 1.