we know that
The area of a square is equal to
[tex]A=b^{2}[/tex]
The perimeter of a square is equal to
[tex]P=4b[/tex]
where
b is the length side of the square
Step 1
Find the length side of the square pillowcase
[tex]A=324\ cm^{2}\\ b^{2}=324\\b=\sqrt{324}\ cm\\ b=18\ cm[/tex]
Step 2
Find the perimeter of the square pillowcase
[tex]P=4*18[/tex]
[tex]P=72\ cm[/tex]
Step 3
Find the cost
we know that
the lace is sold for $0.98 for every 2 centimeters
by proportion
[tex]\frac{0.98}{2}\frac{\$}{cm} = \frac{x}{72}\frac{\$}{cm} \\ \\ 2*x=0.98*72\\ \\x=\$ 35.28[/tex]
therefore
the answer is
[tex]\$ 35.28[/tex]
