Question 1141391
The volume of each rod is  {{{ V = pi*r^2*h  = pi*(4/2)^2*90 }}} = 1130.973 cm^3<br>

Now divide the volume consumed by the volume of each rod:

   {{{ 30520.8/ 1130.973 }}}  = 26.986 (they can make {{{ highlight(matrix(1,2," 26", " rods")) }}}, with just less than one rod's worth of material left over)
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Side note: I ignored the possibility that the stock material has a shape that allows fewer rods to be made.  
Be aware that sometimes the geometry given for the stock material will also come into play.