1. Adreptunghi=Lxl, Pdreptunghi=2(L+l)=30, impartim la 2, L+l=15, L=15-l, L=4l, egalam valorile lui L, 15-l=4l, 5l=15, l=3 cm, L=4l=12cm, A=12x3=36[tex] cm^{2} [/tex]
2. Vbazin=Lxlxh=5x3x4=60[tex] m^{3} [/tex], 200 litri=0,2[tex] m^{3} [/tex], 60:0,2=300 minute dureaza umplerea bazinului