1512 in3 (/7) 216 (/2) 108 (/2) 54 (/2) 27
------------ = ------------ = --------- = -------- = -------
7000 in3 (/7) 1000 (/2) 500 (/2) 250 (/2) 125
the scale factor (ratio) is 27in : 125in
*in case you were wondering what took so long, i was reducing the whole time on a piece of paper*