Question 1169123

let the length be {{{l}}} and the width {{{w}}}

the perimeter of a rectangle is {{{P=2(l+w)}}}

if the perimeter of a rectangle is {{{30m}}} more than {{{three}}} times it's {{{width}}}, we have

{{{P=3w+30m}}}

If the perimeter is {{{84m}}}, then

{{{84m=3w+30m}}}

{{{84m-30m=3w}}}

{{{54m=3w}}}

{{{w=54m/3}}}

{{{w=18m}}}

{{{P=2(l+w)}}}......substitute known variables

{{{84m=2(l+18m)}}}

{{{84m/2=l+18m}}}

{{{42m=l+18m}}}

{{{l=42m-18m}}}

{{{l=24m}}}

so, the length is {{{24m}}} and the width is {{{18m}}}