Question 417943
P = 2(length + width)

{{{90 = 2( length + 21)}}}


{{{90/2 = 2( length + 21)/2}}}

{{{ 45 = length + 21}}}

{{{ 45 -21 = length + 21-21}}}

{{{ 24 = length }}} which makes the perimeter 90
so to make the  perimeter greater than 90, the length should be more than 24.