\(A=2a^2*\red{l}-1,5*a^2*π\)
\(2a^2*\red{l}=A+1,5*a^2*π\)
\(\red{l}=\frac{A+1,5*a^2*π}{2a^2}\)
\(A=2\green {a^2}*l-1,5*\green {a^2}*π=\green {a^2}*(2l-1,5*π)\)
\(\frac{A}{2l-1,5*π}=\green {a^2}\)
\(\green {a^2}=\frac{A}{2l-1,5*π}\)
\(a=±\sqrt{\frac{A}{2l-1,5*π}}\)