Well the conversion of cm to m is 100cm for every meter. This means that depending on the amount of cm you can imagine that the decimal place is moved 2 places over to give you 1. Therefore if you are given 155 cm, after moving the decimal over 2 places you get 1.55 meters. So, since 1.55 m is smaller than 1.6 m, the tablecloth will cover a table that is 1.6 m long.
I hope this helps!