Question

@mathstudent55 Do you think you could help me?

Answer 1

What's your question?

Answer 2

Okay let me upload it okay? Give me 1 minute...

Answer 3

ok

Answer 4

I'm stressing out big time about this.

Answer 5

Don't stress. It's fairly simple once you understand it. Hold on a sec, kay?

Answer 6

I have to type it out.

Answer 7

I have like 10 of these problems and I like just want to cry because I don't know how to do any of them.

Answer 8

Thank you so much. It means a lot :)

Answer 9

Okay, so the lateral area of a three-dimensional figure is basically the surface area of the every single surface, EXCEPT the bases.
So, int he picture. You see the rectangle part. That's the part you want to find the area of.

Answer 10

And we're lucky here. There's a handy-dandy formula for finding the lateral area of a cylinder (which is what this "net" represents)

Answer 11

Okay.

Answer 12

\(\large\tt\ Lateral\ Area\ of\ a\ Cylinder: \)
\(\Large\ 2\pi rh\)
Where, r = radius of base, and h = height

Answer 13

so then it would be 2 * 3.14 * 9 * 17 ?

Answer 14

They give you the height already, 17 mm. They also give you the diameter of the base, 9 mm. Do you know how to find the radius using the diameter?

Answer 15

Not quite @lily1021
9 mm represents the diameter, not the radius.

Answer 16

oh 9 is the diameter. No I don't know how to find the radius using the diameter.

Answer 17

The radius is half the length of the diameter. So what's 9 divided by 2?

Answer 18

4.5

Answer 19

Great. But I just realized something.

Answer 20

Since the formula already has a two in it, you don't even have to divide. Because watch:

Answer 21

\(\large 2\pi(\frac{9}{2})h\rightarrow 2(\frac{9}{2})\pi(17)\rightarrow 9\pi(17)\rightarrow the~answer\)

Answer 22

One last step to the answer. What's 9(17) ?

Answer 23

@lily1021

Answer 24

153?

Answer 25

or is that wrong?

Answer 26

No that's correct. So teh answer is:
\(\large 153\pi\)

Answer 27

That's all. Pretty simple, right?

Answer 28

Wow that's actually pretty simple. So because there is already a 2 in the formula I don't have to divide the diameter by 2 anymore?

Answer 29

right. Exactly.

Answer 30

You did great. :)

Answer 31

Thank you so much

Answer 32

Do you know how I find surface area of a prism? Is there a formula too?

Answer 33

The formula for lateral area of cylinder can either be
\(\large 2\pi rh\)
or
\(\large d\pi h\)
Depending on the information given

Answer 34

Okay so if radius isn't given use the bottom and if it is but not the diameter use the top one. Got it.

Answer 35

Yes, @lily1021 . There is a formula for surface area of a prism.

Answer 36

@lily1021 do you have more questions?

Answer 37

No but I'm trying to find the surface area formula for my next problem . Don't I add all the faces and then multiply by the height?

Answer 38

Um...sorta. How about you close this question and open a new one. Tag me by typing @StudyGurl14

Answer 39

Okay thank you.

Answer 40

anytime :)