we know that
[tex] 1 foot=12inch [/tex]
Since, we have to find 1 foot^2
so, we will take square both sides
[tex] (1 foot)^2=(12inch)^2 [/tex]
[tex] (1)^2 foot^2=(12)^2inch^2 [/tex]
[tex] 1 foot^2=144 inch^2 [/tex]
so, we can see that it is not equal to 12 inch^2
that's why [tex] 1 foot^2=12 inch^2 [/tex] is not true