Question

Find the volume and solve the application. A steel post is 6 ft. long and 6” thick in diameter. If a cubic foot of steel weighs 490 lb., how much does the rod weigh (to the nearest pound)?
1.) 138
2.) 332
3.) 338
4.) 577

Answer 1

Answer:

Answer choice 4.  577 pounds

Step-by-step explanation:

Given a cylindrical steel post with dimensions:

• length/height = 6 ft

• Radius = half of diameter = 0.5 * 6 = 3 inches [converting to feet, we need to divide inches by 12, so we have $\frac{3}{12}=0.25$  feet ]

Volume of a cylinder is given as:

Volume = $\pi r^{2}h$

Substituting all the given values we have:

$V=\pi r^{2}h\\V=\pi(0.25)^{2}(6)\\V=0.375\pi\\V=0.375(3.14)\\V=1.1775$ cubic feet

Since, 1 cubic foot of steel weights 490, 1.1775 cubic foot of steel would weigh  $490*1.1775=576.97$

Rounding to nearest pound, we would get $577$ pounds as the answer.

Answer choice 4 is correct.