Formula: [tex]2width+2length=perimeter[/tex]
[tex]length=15inches[/tex]
[tex]width=?[/tex]
[tex]Perimeter=54inches[/tex]
[tex]2*15=30[/tex] (There are two sides for the length)
[tex]54-30=24[/tex]
[tex]24/2=12 [/tex] (There are two sides for the width)
The width of the desk is 15 inches
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-Geekhawk