A cuboid square steel, 3 meters long, cross-section is 5 cm square, if each cubic decimeter of steel 7.8 kg
3 M = 30 decimeters 5 cm = 0.5 decimeters
0.5 × 0.5 × 30 = 7.5 cubic decimeter
7.5 × 7.8 = 58.5kg
3 M = 30 decimeters 5 cm = 0.5 decimeters
0.5 × 0.5 × 30 = 7.5 cubic decimeter
7.5 × 7.8 = 58.5kg