A square steel is 2.5 meters long. Its cross section is a square with a side length of 6 cm. If the square steel weighs 7.8 kg per cubic decimeter, how many kg does the square steel weigh? Want a formula

A square steel is 2.5 meters long. Its cross section is a square with a side length of 6 cm. If the square steel weighs 7.8 kg per cubic decimeter, how many kg does the square steel weigh? Want a formula

Volume = L * w * h
V=a*b*h
=25×0.6×0.6
=9 cubic decimeter
Mass = 9 × 7.8 = 70.2kg

Paint 4 square columns. The bottom of the square column is a square with side length of 0.2. The height of the square column is 5 meters. It costs 8.6 yuan per square meter. How much does it cost to paint these square columns?

0.2 times 4 times 5 times 8.6 times 4
=0.8 by 5 by 8.6 by 4
=4 by 8.6 by 4
=34.4 times 4
=137.6 yuan
A: it costs 137.6 yuan to paint these square columns

A section of square steel, 2m long, with a cross-sectional area of 25cm2. It is 7.8kg per cubic decimeter of steel. How many kg is this section of square steel?

V=0.25×20=5dm^2
7.8×5=39kg
❤ your question has been answered ~ (> ^ ω)^