Question 829279
Start by making an equation for perimeter.
{{{l+l+w+w=80}}}
now we know that the length is equal to 3 times the width, l=3w, and that width just equals width, w=w.
now since i=3w, we can replace all l's with 3w.
{{{(3w)+(3w)+w+w=80}}}
{{{8w=80}}}
{{{w=10}}}
since w is the width, the width is 10 cm.
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