2 1 over 4 has no meaning. If it is a number, it cannot be expressed as a quantity of length. If it is a length we need to know what unit it is, and secondly what 2 1 over 4 is in proper mathematical format.
1.00
1 foot, rounded to the nearest hundredth is 1 foot!
It is 7.22 rounded to the nearest hundredth
81.00
49.00
3.45
23.06
265.70
304.62
1.00
It is 8.92 when rounded to the nearest hundredth because the digit 1 is less than 5
1 cm is the nearest 0.015