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

1. anonymous
2. butterflydreamer

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

3. anonymous

So it's 150.72?

4. phi

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.

5. anonymous

Oh yeah I remember now

6. anonymous

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

7. anonymous

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

8. phi

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.

9. anonymous

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

10. phi

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.

11. anonymous

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

12. anonymous

Wow

13. phi

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

14. anonymous

Yeah that's where I was getting confused

15. anonymous

So 6 is the Height of the rectangle?

16. anonymous

Lateral area = a) 24 pi square units b) 48 pi square units c) 96 pi square units

17. anonymous

Those were the answer choices shown

18. anonymous

The area of a rectangle is Width times Height

19. anonymous

Base times Height

20. anonymous

It's C. 6 multiplied by 8 equals 48