Step-by-step explanation:
A. First know that
[tex]rectangle \: area \: = \: len \: \times width \: \\ = 12ft\times 18ft \\ = 216 \: ft ^{2} [/tex]
[tex]sq \: area \: = ( one \: side)^{2} \\ = (13ft)^{2} \\ = 169ft^{2} [/tex]
Expression
[tex]cost \: = 169(3.50) + 216(3.50) \: [/tex]
B.
$1347.50
