Mathematics
17 Online
OpenStudy (anonymous):
Three tennis balls are packed tightly in a rectangular box.
What is the ratio of the volume of the tennis balls to the volume of the box?
Join the QuestionCove community and study together with friends!
Sign Up
jimthompson5910 (jim_thompson5910):
It's not 100% clear, but I'm assuming the tennis balls are packed like this
|dw:1399874375587:dw|
jimthompson5910 (jim_thompson5910):
it's not drawn perfectly since the 3 tennis balls are supposed to touch
jimthompson5910 (jim_thompson5910):
anyways, let's say the diameter of one ball is 1 unit
|dw:1399874441199:dw|
what would be the length of the rectangle?
OpenStudy (anonymous):
Yes thats what it looks like. The length of the rectangle would be 3
jimthompson5910 (jim_thompson5910):
good
Join the QuestionCove community and study together with friends!
Sign Up
jimthompson5910 (jim_thompson5910):
what is the width of the rectangle?
OpenStudy (anonymous):
1
jimthompson5910 (jim_thompson5910):
correct
jimthompson5910 (jim_thompson5910):
what is the height of the box?
OpenStudy (anonymous):
Isn't the height the same as the length? so 3?
Join the QuestionCove community and study together with friends!
Sign Up
jimthompson5910 (jim_thompson5910):
not quite
jimthompson5910 (jim_thompson5910):
imagine we have this 3D box
|dw:1399874761408:dw|
jimthompson5910 (jim_thompson5910):
we found the length and width so far
|dw:1399874790789:dw|
jimthompson5910 (jim_thompson5910):
the height is the same as the diameter of each ball (to make sure they fit in terms of the height), so the height is 1
jimthompson5910 (jim_thompson5910):
|dw:1399874819427:dw|
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
Okay, that makes sense
jimthompson5910 (jim_thompson5910):
what is the volume of that rectangular box?
OpenStudy (anonymous):
The volume is 3
jimthompson5910 (jim_thompson5910):
3 cubic units, good
jimthompson5910 (jim_thompson5910):
if a sphere has a diameter of 1, what is the volume of that sphere?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
4.2 cubic units?
jimthompson5910 (jim_thompson5910):
If you used the formula
V = (4/3)*pi*r^3
then you are correct
jimthompson5910 (jim_thompson5910):
but remember the diameter is 1, so the radius would be half that: 1/2 = 0.5
jimthompson5910 (jim_thompson5910):
so you should have
V = (4/3)*pi*(0.5)^3
V = ??
OpenStudy (anonymous):
Oh yeah thats right, so the volume is actually .524. But since there is three of them we times it by 3?
Join the QuestionCove community and study together with friends!
Sign Up
jimthompson5910 (jim_thompson5910):
I'm getting 0.5235987755983, so it looks like you got it