Question

Lateral Area of a Cylinder
Can someone please explain that to me real quick? I completely forgot how to do it.

Answer 1

https://suwannee.owschools.com/media/g_geo_2013/8/group100.gif

Answer 2

lateral area of a cylinder formula:
\[lateral surface area of a cylinder = 2\pi r h\]

Answer 3

So it's 150.72?

Answer 4

If you cut the cylinder, and unrolled it, it would look like a rectangle.
one side would be the (unrolled ) circumference of the circle, and the other side would be the height. The problem becomes: find the area of a rectangle.

Answer 5

Oh yeah I remember now

Answer 6

You use the hight of the cylinder as the length of the rectangle

Answer 7

and the diameter as the width. or is it the other way around?

Answer 8

not the diameter, the circumference (distance around)
take a piece of paper and roll it to form a cylinder (with no top or bottom)
It should be clearer what is going on.

as for which side is height vs width of the rectangle, it's arbitrary what we call each side.

Answer 9

Okay. Is the lateral area the same thing as surface area or no? I'm just wondering

Answer 10

lateral (Latin for side) is the "side area" of the cylinder.... the part you can paint, but not including the top and bottom "circles"
on a can of peas (for example), the lateral area is where the label goes.

Answer 11

Oh that makes so much more sense! Oh My Gosh! I was thinking that lateral area was just another term for surface area

Answer 12

Wow

Answer 13

surface area usually means the *entire* surface (which means for a cylinder you add in the area of the top and bottom)

Answer 14

Yeah that's where I was getting confused

Answer 15

So 6 is the Height of the rectangle?

Answer 16

Lateral area =

a) 24 pi square units
b) 48 pi square units
c) 96 pi square units

Answer 17

Those were the answer choices shown

Answer 18

The area of a rectangle is Width times Height

Answer 19

Base times Height

Answer 20

It's C. 6 multiplied by 8 equals 48