Question 752841
Perimeter of Rectangle = 2l + 2b
Area of Rectangle = l * b

Perimeter of Rectangle
={{{76ft=2l+2b}}} ------------- eqn 1
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Area of Rectangle
={{{72ft^2=l*b}}}

We can remove units and solve.

{{{2l+2b=76}}} --------------- eqn. 1
{{{l*b=72}}} ----------------- eqn. 2

From eqn. 2,
{{{l=(72/b)}}}
Substitute 72/b for l in eqn. 1

{{{2l+2b=76}}}
{{{2b=76-2l}}}
{{{2b=76-2(72/b)}}}
{{{2b=76-(144/b)}}}
{{{2b=(76b-144)/b}}}
{{{2b^2=76b-144}}}
{{{2b^2-76b+144=0}}}
{{{2b^2-72b-4b+144=0}}}
{{{2b(b-36)-4(b-36)=0}}}
{{{(2b-4)(b-36)=0}}}
Either
{{{2b-4=0}}}
OR
{{{b-36=0}}}
Either
{{{2b=4}}} => {{{b=2}}}
OR
{{{b=36}}}

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<br />
When you substitute 
{{{b=2}}} into eqn. 2, you get that {{{l=36}}}
AND
When you substitute
{{{b=36}}} into eqn. 2, you get that {{{l=2}}}

Therefore, dimensions of the rectangle are

l=2 and b=36 OR
l=36 and b=2

Hope I helped!