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what is the surface are of a cylinder with r=8 h=4

Guest Jun 6, 2014

Best Answer 

 #1
avatar+3450 
+16

So we are looking at a cylinder similar to this:

If we were to cut this cylinder apart, it would look like this:

To find the surface area of one of the circles we have to use pi*r2

3.14*82 = ?

3.14*64

=200.96

There are two circles, so we will times this by 2

200.96*2 = 401.92

 

Now that we have the surface area of the two circles, we just need to figure out the surface area of the big rectangle. To figure this out, we will use (2r*pi)*h

2(8)*3.14*4 

= 200.96

 

Now we just add up the two circles + the big rectangle, and we have our surface area.

401.92+200.96 = 602.88

 

The surface area of this cylinder is 602.88 units.

NinjaDevo  Jun 6, 2014
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3+0 Answers

 #1
avatar+3450 
+16
Best Answer

So we are looking at a cylinder similar to this:

If we were to cut this cylinder apart, it would look like this:

To find the surface area of one of the circles we have to use pi*r2

3.14*82 = ?

3.14*64

=200.96

There are two circles, so we will times this by 2

200.96*2 = 401.92

 

Now that we have the surface area of the two circles, we just need to figure out the surface area of the big rectangle. To figure this out, we will use (2r*pi)*h

2(8)*3.14*4 

= 200.96

 

Now we just add up the two circles + the big rectangle, and we have our surface area.

401.92+200.96 = 602.88

 

The surface area of this cylinder is 602.88 units.

NinjaDevo  Jun 6, 2014
 #2
avatar+78575 
0

Very, very nice explanation, NinjaDevo !!!   One of the best I've seen on this site for the surface area of a cylinder. I'd give you 6pts (If I could), but alas, I'm limited to just 3 and a BIG "Thumbs Up."

P.S.  .....I've recommended that this one be highlighted in Melody's "End of the Day" wrap!!

CPhill  Jun 6, 2014
 #4
avatar+90988 
0

I gave you another 3 points.

Thank you for your excellent answer NinjaDivo 

I have included the address of this  answer in the Sticky note: "Information pages worth keeping or developing"

It was CPhill's suggestion but I thought it was a god idea too!

Melody  Jun 7, 2014

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