Question 558202
<pre>
The other tutor is being a smart-ass.  80cm is about right for a standard 
student desk in a classroom.  He should have known this problem was not
about a desk in an office.

To convert 80 centimeters to inches, we put 80cm over 1 like this:

{{{(80cm)/1}}}

and then we use the fact that 1in = 2.54cm to make the unit fraction
{{{1in/(2.54cm)}}} to multiply that by.  We chose the unit fraction with
centimeters on the bottom so it would cancel with the centimeters in 
the top of {{{(80cm)/1}}}.  Multiplying by that unit fraction:

{{{(80cm)/1}}}×{{{(1in)/(2.54cm)}}}

Then we cancel the cm's:

{{{(80cross(cm))/1}}}×{{{(1in)/(2.54cross(cm))}}}
 
And we have

{{{(80*1in)/2.54}}}

{{{(80in)/2.54}}}

And we divide 80 by 2.54 and get

31.49606299 inches

which you'd probably round off to 31.5 inches.

Edwin</pre>