$a)k^2=4^2=16$  

$\frac{P_{\text{A’B’C’D’}}}{12{\text{cm}}^2}=16\mid \cdot 12{\text{cm}}^2$  

$P_{\text{A’B’C’D’}}=\underline{\underline{192{\text{cm}}^2}}$  

$b)k^2={\left(\frac{1}{4}\right)}^2=\frac{1}{16}$  

$\frac{P_{\text{A’B’C’D’}}}{12{\text{cm}}^2}=\frac{1}{16}\mid \cdot 12{\text{cm}}^2$  

$P_{\text{A’B’C’D’}}=\frac{12}{16}{\text{cm}}^2$

$P_{\text{A’B’C’D’}}=\underline{\underline{\frac{3}{4}{\text{cm}}^2}}$  

$c)k^2={\left(\sqrt{2}\right)}^2=2$  

$\frac{P_{\text{A’B’C’D’}}}{38{\text{cm}}^2}=2\mid \cdot 38{\text{cm}}^2$  

$P_{\text{A’B’C’D’}}=\underline{\underline{76{\text{cm}}^2}}$  

$d)k^2={\left(0,75\right)}^2={\left(\frac{3}{4}\right)}^2=\frac{9}{16}$  

$\frac{P_{\text{A’B’C’D’}}}{48{\text{cm}}^2}=\frac{9}{16}\mid \cdot 48{\text{cm}}^2$  

$P_{\text{A’B’C’D’}}=\frac{9}{{\sout{16}}^1}\cdot {\sout{48}}^3{\text{cm}}^2=\underline{\underline{27{\text{cm}}^2}}$