How tall isn't a stack of 100 pennies in centimeter?

A stack of 100 pennies is approximately 2.5 centimeters tall. Since a single penny is about 1.9 millimeters thick, stacking 100 of them results in a height of roughly 190 millimeters, which converts to 19 centimeters. Therefore, a stack of 100 pennies is not 0 centimeters tall; it is actually 19 centimeters tall.