#### dennis98

I have a question, and I cannot figure out why my theory does not work.

Say we have a circle tablecloth with 48 inch diameter.

This clearly has an area of 576 pi.

Now let's say this same tablecloth is put over a 36 inch table. It now takes the shape of a cylinder without a bottom, with a height of six inches on each side and a diameter of 36. So why does the modified cylinder formula [2(pi)(18)(6) + pi(18)^2] not equal the same area of 576 pi, but a lesser 540 pi?

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#### v8archie

Math Team
Because it's not a cylinder, the sides don't hand straight down.

1 person

#### greg1313

Forum Staff
Think about what happens to the circumference of the table cloth.

#### dennis98

Thank you both very much

#### CRGreathouse

Forum Staff
This is a good question, and I really like the thought process you used to come up with it. I think both of the answers are helpful in giving you the right intuition here. Good luck!

#### manishsqrt

You mentioned that it will become a cylinder with no bottom, the formula which you are using is for closed cylinder's area, but your cylinder is open at one base.This means from the expression you must subtract the area of the circular part of the table.

#### Denis

Math Team
Well, you could always cut a 36d-circle from your 48d-tablecloth,
then play with the 6wide ring leftover...
perhaps practice throwing it so it rings around the microwave oven...

Got a better idea, Archie?