help

May 2010
53
1
Altlanta GA
Volume of a Sphere = 4
3
πr3 The radius of a softball is almost 2 inches. The radius of a basketball is almost 5 inches How would the volume of a basketball compare to the volume of a softball ?
A)
About 2.5 times that of the softball
B)
About 7.5 times that of the softball
C)
About 6.25 times that of the softball
D)
About 15.625 times that of the softball


how do you do it?
 
May 2010
53
1
Altlanta GA
ok, i got D, not sure how though??

any explenations??
 

e^(i*pi)

MHF Hall of Honor
Feb 2009
3,053
1,333
West Midlands, England
Volume of a Sphere = 4
3
πr3 The radius of a softball is almost 2 inches. The radius of a basketball is almost 5 inches How would the volume of a basketball compare to the volume of a softball ?
A)
About 2.5 times that of the softball
B)
About 7.5 times that of the softball
C)
About 6.25 times that of the softball
D)
About 15.625 times that of the softball


how do you do it?

\(\displaystyle V_s = \frac{4}{3}\pi r_s^3\)

\(\displaystyle V_b = \frac{4}{3}\pi r_b^3\)

The ratio is given by \(\displaystyle \frac{V_b}{V_s} = \frac{\frac{4}{3}\pi r_b^3}{\frac{4}{3}\pi r_s^3} = \frac{r_b^3}{r_s^3}\)

You know \(\displaystyle r_b\) and \(\displaystyle r_s\) so plug in and solve
 
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