altezza h = 54 cm
base b = 5h/9 = 54/9*5 = 30 cm
area A = 54*30 = 1.620 cm^2
54*5/9=30=b A=30*54=1620cm2
54*5/9=30 (b) A=30*54=1620cm2
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Base $\small b= \dfrac{5}{9}×h = \dfrac{5}{\cancel9_1}×\cancel{54}^6 = 5×6 = 30\,cm;$
area $\small A= b×h = 30×54 = 1620\,cm^2.$