What is the approximate of 3.4545454

3 and 5/11 is 3.45454545...

Just to add a bit more theory, repeating decimals can be replicated by taking the replicating part and dividing by the number of 9's in the length of the repeating section.

For example:
0.4444... = 4/9
0.373737... = 37/99
0.123123123... = 123/999

So for your example, the fraction is 3 + 45/99, which ebaines then simplified.