Question 784681
The volume of a sphere is {{{4/3 * pi * r^3}}}<P>
To find how many Plutos fit into Earth, divide Earth's volume by Pluto's volume.  4/3 and pi all cancel.  So divide Earth's radius cubed by Pluto's radius cubed, or divide Earth's radius by Pluto's radius, then cube the result.
{{{(6371/1161)^3 = 165.24417...}}} = approximately 165 Pluto spheres have the same volume as one Earth sphere.