Surface Area of a Cone – Let’s Figure it out….

TabletClass Math:


Math Notes:

[jefflax]

John, I actually admire you for finding a new topic each day and speaking of it from your heart. That is the way to teach. I've taken for granted the many hours it took me to find the answer. It's lessons like yours is how I learned. Thank you and carry on and I hope my previous negative comments didn't hurt you. Now, back to the video already in progress

[NatalieCuidon]

So helpful, thank you! I've been watching your videos and it's been helping me through studying for my ged. I truly appreciate what you're doing.

[michaelsmagala]

You have made a mistake. Think about it. Suppose you had a tube with the bottom diameter =4 and the height =7. The surface area would be equal to 2Xcircle area and the area around the outside of the tube. Now suppose you could convert the circle into an equal square and used that to create a square tube of equal volume to the round tube. The surface area would be equal to the 2 squares and 4X the rectangles, correct?
Now if you cut the square tube from one top side down to the opposite side you would have two equal volumes but the surface area would be the original area plus 2X the sliced area.
So let’s do that. Radius 2=diameter 4. A circle with diameter 4 has the same area as a square with sides =3.265986. That
3.265986X7=22.8619X4=91.4476
91.4476+21.3333=112.78095
This is the surface area of a square tube that has equal volume to a round tube with a radius of 2.
When we divide the total surface area by 2 we get 56.39!!! The answer you got for the surface area of a cone which would have exactly half the volume of a tube….. but we know that the surface area for 2 parts MUST be greater!!!
I’m not going to go over the correct math right now but for your information the correct surface area for the cone with a radius of 2 and a height of 7 is 81.62 or 26pi.

[michaelsmagala]

Oops, made a mistake but your answer is still wrong also. Should be 56.3898, not 54

[WisdomUnvield]

No offence but thats the worst explanation I have ever seen cant you draw an opened cone can explain how? Also half of the thime your just talking about random stuff no one wants to hear