b=27*2/3=18 A=(18+27)*20/2=450cm2
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Base maggiore $\small B= 27\,cm;$
base minore $\small b= \dfrac{2}{3}B = \dfrac{2}{\cancel3_1}×\cancel{27}^9 = 2×9 = 18\,cm;$
altezza $\small h= 2\,dm = 2×10 = 20\,cm;$
area $\small A= \dfrac{(B+b)×h}{2} = \dfrac{(27+18)×\cancel{20}^{10}}{\cancel2_1} = 45×10 = 450\,cm^2.$
A = (B + b) * h / 2;
B = 27 cm;
b = 27 * 2/3 = 18 cm;
h = 2 dm = 20 cm;
A = (27 + 18) * 20 / 2 = 450 cm^2;
A = 4,50 dm^2.
@sophia_sera ciao.