How many square tiles each of side 8cm
are needed to tile a floor 22m 40cm long by 12m
80 cm wide

Step-by-step explanation:

Since the tiles are in cm let's get the whole floor into those units.

22m and 40 cm = 2200cm and 40 cm =2240

12 m and 80 cm = 1280 cm.

Now, let's make sure that the tiles will fit both along the length and width.  since the tiles are 8 cm long and wide the floor needs to be divisible by 8 along its length and width.  If it weren't, say  you wanted to tile a floor 81 cm long, well you'd be able to line up 10 of those tiles  but then there would be 1 cm of blank space.  

You can use a calculator to check, or a number of other methods, I am going to divide both measurements by 2 three times.  because 2*2*2 is 8, so x/(2*2*2) would be the same as x/8.  As long as we get a whole number we know it's divisible by 8.

2240/2 = 1120/2 = 560/2 = 280  Yep, divisible by 8.

1280/2 = 640/2 = 320/2 = 160  Also divisible by 8.  So the tiles will perfectly fit on the floor.

Now that we know that we can take the area of the floor and divide it by the area of a tile.  so that's (2240*1280)/(8*8)

(2240*1280)/(8*8)

2867200/64

44800

So it will take 44800 tiles.  

Let me know if there's anything you didn't understand.  

sorry man i accidentally pressed yes my bad

step-by-step explanation: