How do you measure a room for 18inch tile when the room is 19 feet by 10 feet?

Answer 1

The area of the room is 19*10 = 190 sq ft

Each tile is 1.5 ft *1.5 ft = 2.25 sq ft

So, you need an absolute minimum of 190/2.25 = 84.44... rounded up = 85 tiles.

However, that assumes that the offcuts can be used for tiling, and that you don't mind an area full of tiny bits. It would be more sensible to work along the following lines:

19 feet/1.5 ft = 12.67 rounded up = 13 tiles across the length

10 feet/1.5 ft = 6.67 rounded up = 7 tiles across the width.

So you would need 13*7 = 91 tiles and in this case offcuts do not need to be used.

Finally, if this is a real-life question, rather than a mathematical exercise, you would be well advised to make some allowance for wastage.