18 ft = 548.64 cm
It depends on the units used for 18 by 18. For example, two tiles of 18 ft x 18 ft will be enough. On the other hand, you will need just over 1000 tiles measuring 18 cm x 18 cm.
1 ft = 30.48 cm So... 2.9 ft × 30.48 cm/ft = 88.392 cm
in 1 cm there is 0.0328084 ft
1.5 ft = 18 inches = 18*2.54 cm = 45.72 cm =457.2 mm
3.6 ft is 109.72800 cm
6.3 ft = 192.024 cm
883 ft = 26,913.84 cm
176 cm = 5.77 ft
205 ft = 6,248.4 cm
22.2 ft = 676.656 cm
13 ft = 396.24 cm
3.5 ft = 106.68 cm