Al=3·12·30=1080cm²
V=Ab·h=l²√3/4·h=12²√3/4·30=144√3/4·30=36√3·30=1080√3cm³
1080√3:2=540√3 este volumul jumatate
540√3cm³=540·1,73=934,2cm³=0,9342dm³=0,9342l
V=l³=20³=8000cm³=8dm³=8l are vasul cubic
x=0,9342·20/8=2,3355 inaltimea la care saridicat apa in vasul cubic
Vcub/Vvaza=8l/1,8684=4,28