Question 395684


let the length be {{{a}}}, and the width be {{{b}}}

given:

{{{P =126cm}}}

{{{a:b=5:2}}}......=>  {{{2a=5b}}}.......=>.......{{{a=5b/2}}}


{{{P =126cm}}}

{{{126cm=2(a+b)}}}.......substitute {{{a=5b/2}}}

{{{126cm=2((5b/2)+b)}}}

{{{126cm=(10b/2)+2b)}}}

{{{126cm=(cross(10)5b/cross(2))+2b)}}}

{{{126cm= 5b+2b}}}

{{{126cm= 7b}}}

{{{126cm/7= b}}}

{{{18cm= b}}}.............now find {{{a}}}


{{{a=5b/2}}}

{{{a=5*(18cm)/2}}}


{{{a=5*(cross(18)cm)/cross(2)}}}

{{{a=5*(9cm)}}}

{{{a= 45cm}}}

check:

{{{126cm=2(a+b)}}}

{{{126cm=2(45cm+18cm)}}}

{{{126cm=2(63cm)}}}

{{{126cm=126cm)}}}