Question

A right circular cylindrical metallic rod is 16 inches tall. The radius of the base is 4 inches. What is the surface area of this metallic rod, in terms of π? the choices are 150π 140π 145π and 160π​

Answer 1

`144\pi \: or \: 145\pi`

SA to cylinder is

`2\pi \: rh + \pi \: r {}^(2)`

=2

`2 * \pi * r \\ * h + \pi * r {}^(2)`

2

`2\pi * 4 * 16 + \pi * 4 * 4`

answer =

`144\pi \: to \: 145\pi`

Answer 2

160π

Explanation:

The surface area of a right circular cylinder can be calculated using the following equation:

`\boxed{\mathrm{Surface \ area = }2 \pi rh + 2 \pi r^2}` ,

where h is the height and r is the radius of the base of the cylinder.

We are told that the rod is 16 inches tall, therefore h = 16. We are also told that the radius of the base is 4 inches, therefore r = 4. Using this information along with the formula above, we can calculate the surface area of the metallic rod:

Surface area =
`(2 * \pi * 4 * 16) + (2 * \pi * (4)^2)`

=
`128\pi + 32\pi`

=
`\bf 160\pi`

Therefore the surface area of the metallic rod is 160π.