38 a. V = l × b × h = 16 cm × 18 cm × 16 cm = 4 608 cm3
b. m = ρ × V = 2,17 × 4 608 g = 9 999 g (afgerond 10 kg)
39 a. m = ρ × V = 11,30 × 500 g = 5 650 g = 5,65 kg
b. m = ρ × V = 0,80 × 1 500 g = 12 000 g = 1,2 kg
c. V = m/ρ = (1 000)/(0,80 ) cm3 = 1 250 cm3 = 1,25 dm3
d. V = m/ρ = (2 500)/(2,3 ) cm3 = 1087 cm3 (= 1,1 dm3)