A piece of cuboid steel is 2 meters long and its cross-section is a square with side length 4 cm. Just weighs 7.8 grams per cubic centimeter, how many grams does this square steel weigh?
一段长方体钢材，长2米，横截面是边长4厘米的正方形．每立方厘米刚重7.8克，这块方钢重多少克？
<result>24_690</result>