Question

Justin's company makes solid balls out of scrap metal for various industrial uses. For one project, he must make lead balls that have a radius of 7.5in . If lead costs $0.36 per in3 , how much will the lead cost to make one ball?

Answer 1

Volume of a sphere = 4/3 Pi r³

if r = 7.5

= 4/3 pi 7.5³

= 4/3 pi 421.87

= 1687.5/3 pi

= 562.5 Pi

= 1767.15 in³

then

1767.15 x 0.36 = 636.17

if 1 in³ costs 0.36$

then 1767.15 in³ costs 636.17$

Answer 2

$636.17

Explanation:

First, we need to find the volume of the ball. Then, we will solve for the cost of it.

Volume of a sphere and solving for the area:

V =
`(4)/(3)`πr³

V =
`(4)/(3)`π(7.5)³

V ≈ 1767.15 in³

Now that we have the volume, next we need to find the cost. Since the lead costs $0.36 per in³, and our volume is in in³, we can multiply the volume by the cost.

1767.15 in³ * $0.36 = 636.174

Money rounds to the hundredth place,

636.174 -> $636.17

It will cost $636.17 to make one ball.