l1=V 38,88*3/4=5,4 l2=5,4*4/3=7,2 d=V 7,2^2+5,4^2=9
2p=2*(7,2+5,4)=25,2 l rombo=25,2/4=6,3
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$\small\text{Rettangolo:}$
$\small\text{dimensione minore: } l_1= \sqrt{A÷\dfrac{3}{4}} = \sqrt{38,88×\dfrac{4}{3}}=\sqrt{\dfrac{1296}{25}} = \dfrac{36}{5} = 7,2\,cm;$
$\small\text{dimensione maggiore: } l_2= \dfrac{A}{l_1} = \dfrac{38,88}{7,2} = 5,4\,$
$\small\text{perimetro: } 2p= 2(l_1+l_2) = 2(7,2+5,4) = 2×12,6 = 25,2\,cm;$
a) $\small\text{diagonale: } d= \sqrt{(l_1)^2+(l_2)^2} = \sqrt{7,2^2+5,4^2} = 9\,cm\quad\text{(teorema di Pitagora)}.$
$\small\text{Rombo isoperimetrico:}$
$\small\text{perimetro: } 2p= 25,2\,cm;$
b) $\small\text{lato: } l= \dfrac{2p}{4} = \dfrac{25,2}{4} = 6,3\,cm.$
h = 3b/4
area A = 38,88 = b*3b/4 = 3b^2/4
base b = √38,88*4/3 = 7,20 cm
altezza h = 7,20*3/4 = 5,40 cm
perimetro 2p = 2(7,20+5,40) = 25,20 cm
diagonale d = √7,20^2+5,40^2 = 9,0 cm
spigolo s = 25,20/4 = 6,30 cm