Question 549091
A stack of 25 U. S. nickels has a height of approximately 1.925 inches.  What is the value, in dollars, of a 7-foot high stack of U. S. nickels?  Express your answer to the nearest cent.  Show or explain how you got your answer.
<pre>
This is the proportion:

height of short stack of nickels   value of short stack of nickels
———————————————————————————————— = ————————————————————————————————— 
height of tall stack of nickels     value of tall stack of nickels
 
But we must first change the 7 feet height of the tall stack to inches.

{{{7ft/1}}}×{{{(12in)/(1ft)}}} = {{{7cross(ft)/1}}}×{{{(12in)/(1cross(ft))}}} = 84in

and we change the 25 nickels to money 

{{{(25nickels)/1}}}×{{{"$.05"/(1nickel)}}} = {{{(25cross(nickels))/1}}}×{{{"$.05"/(1cross(nickel))}}} = $1.25

And we let x be the value in money of the tall stack.

Now we substitute in the above proportion:

 1.925    $1.25   
 ————— = —————— 
   84       x

Now we cross multiply:

1.925x = ($1.25)(84)

1.925x = $105

Divide both sides by 1.925

{{{1.925/1.925}}}x = {{{"$105"/1.925}}}

     x = $54.54545455

That rounds to  $54.55.

Edwin</pre>