78.8 rounded to the nearest tenths is 78.8
We can not round it to the tenths because it already is rounded to the tenths.
1) We calculate the volume of a metal bar (without the hole).
volume=area of hexagon x length
area of hexagon=(3√3 Side²)/2=(3√3(60 cm)²) / 2=9353.07 cm²
9353.07 cm²=9353.07 cm²(1 m² / 10000 cm²)=0.935 m²
Volume=(0.935 m²)(2 m)=1.871 m³
2) we calculate the volume of the parallelepiped
Volume of a parallelepiped= area of the section x length
area of the section=side²=(40 cm)²=1600 cm²
1600 cm²=(1600 cm²)(1 m² / 10000 cm²=0.16 m²
Volume of a parallelepiped=(0.16 m²)(2 m)=0.32 m³
3) we calculate the volume of a metal hollow bar:
volume of a metal hollow bar=volume of a metal bar - volume of a parallelepiped
Volume of a metal hollow bar=1.871 m³ - 0.32 m³=1.551 m³
4) we calculate the mass of the metal bar
density=mass/ volume ⇒ mass=density *volume
Data:
density=8.10³ kg/m³
volume=1.551 m³
mass=(8x10³ Kg/m³ )12. * (1.551 m³)=12.408x10³ Kg
answer: The mas of the metal bar is 12.408x10³ kg or 12408 kg
1 ton is equivalent to 2000 pounds
we have to find how many pounds 3 3/8 tons are equal to
if 1 ton --> 2000 pounds
we can break down the fraction into 3 + 3/8
then 3 tons --> 2000 x 3 = 6000 pounds
3/8 ton ---> 2000 x 3/8 = 
after adding 6000 + 750 = 6750 pounds
answer is 6750 pounds
