h=16*9/4=36 A=36*16=576 l quad.=V 576=24 2p=24*4=96cm
D=24*V 2 cm
==================================================
$\small\textbf{Rettangolo:}$
$\small\text{altezza } h= \dfrac{9}{4}b = \dfrac{9}{\cancel4_1}×\cancel{16}^4 = 9×4 = 36\,cm;$$
$\small\text{area } A= b×h = 16×36 = 576\,cm^2.$
$\small\textbf{Quadrato equivalente:}$
$\small\text{area } A= 576\,cm^2;$
$\small\text{lato } l= \sqrt{A} = \sqrt{576} = 24\,cm;$
$\small\text{perimetro } 2p= 4×l = 4×24 = 96\,cm;$
$\small\text{diagonale } d= l·\sqrt2 = 24·\sqrt2\,cm.$