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xRAWRRx3
Group Title
Please help. :(
In the figure below, rectangle ABCD is rotated about side AB.
If Ab = 10 and BC = 4 , what is the volume of the resulting solid?
 2 years ago
 2 years ago
xRAWRRx3 Group Title
Please help. :( In the figure below, rectangle ABCD is rotated about side AB. If Ab = 10 and BC = 4 , what is the volume of the resulting solid?
 2 years ago
 2 years ago

This Question is Closed

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
dw:1338516177766:dw
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
First, it helps to figure out what solid figure you'll get if you rotate this
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
Any ideas of what type of solid figure it will be?
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
i have no clue.
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
Imagine spinning this around AB (think of AB as stuck to the ground) and this rectangle is like a door. What you'll get is a cylinder.
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
How'd you get that? Is that like common sense or something?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
I'm imagining it in my mind really, but you can grab a rectangular object and spin it along a side. You'll see that it traces out a cylinder.
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
then i guess by rotates they mean folded kinda??
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
like rolled up?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
no it's not folding in any way
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
one moment while I track down an animation of this
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
okay, thank you.
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
hmm not finding much sadly, but think of a propeller blade
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
It's alright. I got it. so what do i do after?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
When it's not moving, it's in one spot...but when it spins, it resembles a circle correct?
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
Oh. Okay. So its a cyclinder. what do i do after?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
what's the height of the cylinder?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
and what's the radius of the top of the cylinder?
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
but isn't the circumference 4?
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
since the whole side BC is 4?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
that's not the circumference
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
that's actually the radius since that's as far as it goes in that direction
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
dw:1338517802914:dw
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
dw:1338517841316:dw
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
The rectangle will rotate about that dotted line (which is AB) to create that cylinder. So that's why the radius is 4.
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
I don't really get how its four...
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
Do you see how that cylinder is created?
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
how'd you get it? i still dont get how you created the cylinder like that..
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
I spun the rectangle around that dotted line. The cylinder represents the space that the rectangle carves out (think of the spinning rectangle as a saw or drill cutting into wood)
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
but how is the radius 4? wouldn't it be 2?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
no, the radius is shown in the next drawing dw:1338519158344:dw
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
and that length is exactly the length of BC
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
oh, so AB stays in one spot and The rest of the rectangle kinda like spun around to make the cylinder?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
exactly, AB never move at all but the other points spin/move around
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
A and B never move as well
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
ohhh, i get it. so is the answer 160 pi?
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
you nailed it
 2 years ago

xRAWRRx3 Group TitleBest ResponseYou've already chosen the best response.1
Yay :) thank you so much x)
 2 years ago

jim_thompson5910 Group TitleBest ResponseYou've already chosen the best response.1
you're welcome
 2 years ago
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