Răspuns :
Vcub=lxlxh
L=l=h la cub muchiile sunt egale
Vcub=L³
Vapa=Lxlx3xh/5=75⇒75=5x5x3
⇒L=l=5dm
h=3/5xh=3dm
h=L=3x5:3=5dm
Volumul apei ... V = l² × (3/5×l) = 75dm³
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l ³ = 75 × 5 : 3 =125 deci: l = 5 dm.
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l ³ = 75 × 5 : 3 =125 deci: l = 5 dm.