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A hollow crystal is made of glass that is 3 cm thick. The ball has a radius to the outside surface of 8 cm.

What is the approximate volume of glass used to make the ball?


Use 3.14 to approximate π

 Mar 1, 2019
 #1
avatar+19832 
+1

Volume of the 8cm sphere - volume of 5 cm sphere = glass volume

volume of a sphere = 4/3 pi r^3     Get your calculations on !

= 4/3 pi (8^3 - 5^3)   = 516 pi = 1620.2 cm^3

 Mar 1, 2019
edited by Guest  Mar 1, 2019
edited by Guest  Mar 1, 2019
 #3
avatar+67 
-1

you need to account for both sides...

-DBZ

DivideByZero  Mar 1, 2019
 #5
avatar+19832 
0

No you don't......you are dealing with radii     one radius is  8 the inner is 5

ElectricPavlov  Mar 1, 2019
 #7
avatar+67 
-1

whoops!!! sorry! Guess i dont know what im talking about

indecision

DivideByZero  Mar 1, 2019
 #2
avatar+67 
-1

since it is hollow, you need to take the whole volume minus the air inside

 

 

heres a diagram ish

 

  |       |                      |       |

|       |         inside         |       |<------- outside glass

  |       |                      |       |

    3cm     2cm            3cm

 <<---------8cm-------------->>

so, thats the ball

now we find volume

v=4/3 pi r2

8cm= 2144.66 cm

2cm=33.51cm

2144.66-33.51= 2111.15cm^2

hope that helped

-DBZ

wink

 Mar 1, 2019
 #4
avatar+19832 
0

Ooops....dbz      volume  is 4/3 pi r^3

 Mar 1, 2019
 #6
avatar+67 
-1

i put it in the google calc so either way it would be the same, i just messed up the formula, sorry

DivideByZero  Mar 1, 2019

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