a)[tex]A= l^{2} =(12 \sqrt{2} ) ^{2} =12 ^{2} *2=144*2=288cm ^{2} [/tex]
[tex]P=4L=4* 12 \sqrt{2} =48 \sqrt{2} [/tex]
b)[tex]A= l^{2} =(18 ) ^{2} =18 ^{2} =324cm ^{2} [/tex]
[tex]P=4L=4* 18 =72cm[/tex]
c)[tex]A= l^{2} =(a \sqrt{2} ) ^{2} =2a ^{2} cm ^{2} [/tex]
[tex]P=4L=4* a \sqrt{2} =4a\sqrt{2} [/tex]
d)[tex]A= l^{2} =(x ) ^{2} =x ^{2}[/tex]
[tex]P=4L=4* x =4xcm[/tex]
