Math problems

[invictus]

Your mistake was calculating the volume of the cylinder instead of its surface area.

Yeah, that was my first mistake... I was refering to my second mistake in the post you quoted.

[Ethereal]

Formally, here is the answer:

Surface area of a cylinder = [2*pi*radius*height] + [2*pi*(r^2)]

The ends of the cylinder are 8 feet across and the cylinder is 40 feet long, so we have r = 4 and h = 40.

Therefore, SA = (2*pi*4*40) + [2*pi*(4^2)] = (320*pi) + (2*pi*16) = (1005.3) + (100.5) = 1105.8 square feet

However, because the cylinder is open at both ends, you do not include the surface area of the circle at each end of the cylinder.

So the surface area of the cabin is just 1005.3 square feet.

[RMNIXON]

It does not matter because planes exist simply because people need them................

[carolina73]

I won't answer anymore. It's cheating. I spend my day doing calculations and formulas for new products and cost based pricing.

[Mechanic]

If Apple were to build an electric car would it come with windows?

[carolina73]

If Apple were to build an electric car would it come with windows?

That would mean the last thing you would see is "the blue screen of death".

[RichardMZhlubb]

It's just a standard cylinder with two open ends. It would look like this:

Attachment 41401

The openings at each end are 8 feet across and the cylinder is 40 feet long.

That is all the information you need to calculate its surface area.

That’s not what you originally posted. You said there were two openings at each end.

[carolina73]

That’s not what you originally posted. You said there were two openings at each end.

It would not mater if there was swiss cheese on the end. The cylinder. Nothing on the ends would be part of a cylinder. You can put ends on a cylinder but they are not part of the calculation of the cylinder. You can cap a cylinder but the caps are not part of the cylinder. You would calculate them separately.

[invictus]

That’s not what you originally posted. You said there were two openings at each end.

I see what you're saying but I think he meant one at each end.

[RichardMZhlubb]

It would not mater if there was swiss cheese on the end. The cylinder. Nothing on the ends would be part of a cylinder. You can put ends on a cylinder but they are not part of the calculation of the cylinder. You can cap a cylinder but the caps are not part of the cylinder. You would calculate them separately.

I was not trying to be difficult. I was simply noting that it wasn't possible to know the diameter of the ends based on his original question.