Question

Which of the following is the surface area of the right cylinder below?

height 2
radius 9

A. 174 units2
B. 187 units2
C. 198 units2
D. 162 units2

Answer 1

Answer: The surface area of right cylinder is
`198\pi \text{ units}^2`

Explanation:

To calculate the total surface area of cylinder, we use the formula:

`\text{Total surface area of cylinder}=2\pi r(r+h)`

where,

r = radius of cylinder = 9 units

h = height of the cylinder = 2 units

Putting values in above equation, we get:

`\text{Total surface area of cylinder}=2\pi * 9(9+2)\\\\\text{Total surface area of cylinder}=2\pi * 9* 11\\\\\text{Total surface area of cylinder}=198\pi \text{ units}^2`

Hence, the surface area of right cylinder is
`198\pi \text{ units}^2`

Answer 2

The lateral area of a cylinder (i.e. without the bottom and top lids) is 2πrh = 2π(9)(2) = 36π

The area of the two lids is 2[π(r^2)] = 162π

The sum is: 36π + 162π = 198π

I guess the answers included π but you couldn't type it.