Question 395355


perimeter of rectangle {{{P}}} is {{{20 ft}}} 
the width of rectangle{{{b}}} is {{{4 ft}}} {{{less}}} than {{{length}}} {{{a}}}

or

{{{P = 20 ft}}} 

{{{b + 4ft = a}}}


 find the dimentions of the rectangle

{{{P = 2(a+b)= 20 ft}}} 

{{{2((b + 4ft) +b)/2= 20/2 ft}}} 

{{{(2b + 4ft)= 10 ft}}}

{{{2b = 10 ft - 4ft}}}

{{{2b = 6 ft}}}

{{{2b/2 = 6 ft/2}}}

{{{b = 3ft}}}..........width

now find the length {{{a}}}

{{{3ft + 4ft = a}}}

{{{7ft = a}}}.........length


then find its area {{{A}}} 

{{{A = ab}}} 

{{{A = 7ft*3ft}}}

{{{A = 21ft^2}}}