Gobs of Globes is a specialty store which carries a variety of globe-related products. One of their popular products is a globe piggy bank. The standard one they carry has a volume of 500/3 cubic inches. A customer has asked for a custom-made version with a radius double the size of the standard one. Based on this information, what will be the radius of the custom-made version?
25??

Question

Gobs of Globes is a specialty store which carries a variety of globe-related products. One of their popular products is a globe piggy bank. The standard one they carry has a volume of 500/3 cubic inches. A customer has asked for a custom-made version with a radius double the size of the standard one. Based on this information, what will be the radius of the custom-made version?
 25??

apoorvk · Answer

The volume 'V' of a sphere of radius 'r' is:

$$V=\frac{4}{3}\pi (r)^3$$


Now what happens to the volume when 'r' becomes '2r'?

apoorvk · Answer

@suzy4321

anonymous · Answer

hm im confused i know radius is 6 x6 example but 2r

apoorvk · Answer

Okay, what is (2r)^3?

anonymous · Answer

8r

apoorvk · Answer

It's = 2r*2r*2r = 8r^3 ---> right?

yeah, so 
8r^3 is 8 times of r^3 - am i correct?

apoorvk · Answer

so, when I am doubling the radius, the volume becomes '8' times the initial one - do you understand how?

anonymous · Answer

yes like going backwads

apoorvk · Answer

'backwards'? you mean back-calculating? yeah, in a way..

so, what is the new volume then?

apoorvk · Answer

???

anonymous · Answer

4/3r3
500/3 in=	4/3r3
125 in3	=	r3
5 in	=	r
soo ten

anonymous · Answer

so much rushing for that jaja

apoorvk · Answer

oops lol, i was thinking all the time that we need to find the new volume :/

Yeah, you're right, @suzy4321