Question

The radius of the base of a cylinder is 38 mm and its length is 51 mm. Find the surface area of the cylinder in terms of pi.
A) 6726 pi mm^2 B) 6853 pi mm^2 C) 6764 pi mm^2 D) 6713 pi mm^2

Answer 1

You have to add the area of the top and bottom and then add the area of the "side".

Top and bottom: 2(pi)r^2

Side: (2)(pi)(r)(length)

Make substitutions on r and length and then add them. You are given r and length.

Answer 2

The area of the top and the bottom is simply the area of a circle. The factor of "2" comes into play because of there being 2 surfaces (top and bottom).

The area of the side is conceptually the unravelling of the side, like peeling off a label off of a can to get a rectangle. The width is the circumference of the top or bottom, hence 2(pi)r for the width

Answer 3

That's the general solution and should guide you to be able to get the surface area of any right cylinder. All you have left is simply to plug in the numbers and do the arithmetic.

Answer 4

All good now?

Answer 5

I got C I think that is correct thx so much (:

Answer 6

Good work!

Answer 7

you get good work when you have good help (:

Answer 8

You know what?

Answer 9

what?

Answer 10

You might not believe this, but since I had a day off, I was helping a lot of students today, and I've been helping on Openstudy for a while now, and you're one of the very few students who will actually do any work.

Answer 11

I like to work for what I get. I just really struggle with math and get frustrated easily with it but thx so much!

Answer 12

Well, it was nice working with you and thx for the recognition medal. Good luck to you!