Question 729580
We want both measurements in the same units
There are 100 centimeters in a length of 1 meter, so the conversion for square meters to square centimeters goes like this:
{{{1m^2=(1m)(1m)=(100cm)(100cm)=10000cm^2}}}
So {{{17.5m^2=17.5m^2(10000cm^2/1m^2)=175000cm^2}}}
To tile a surface with an area of {{{17.5m^2=175000cm^2}}}
using tiles with a surface area of {{{625cm^2}}} per tile, we need
{{{175000/625=280}}}tiles.
If the home improvement store would lend you a calculator, it is easy to do that division. Or maybe you brought a calculator, or there is a calculator function in your cell phone. Or maybe you would enjoy doing that calculation with pencil and paper.
 
An easier calculation:
We are using tiles such that each has a surface area of
{{{625cm^2=(25cm)(25cm)}}}
How many of those tiles do we need per {{{m^2}}} of floor?
{{{1m^2=(1m)(1m)=(100cm)(100cm)}}}
{{{(100cm)(100cm)/((25cm)(25cm))=(100cm/25cm)(100cm/25cm)=4*4=16}}}
At {{{4*4=16}}} tiles per {{{m^2}}} we will need
{{{17.5*(4*4)=(17.5*4)*4=70*4=280}}} tiles.
That is how I could calculate it in my head.