2) If you only have numbers, GUESSTIMATE! 13X12X29 is close to
   15x10x30 - not exact but close. 15x10=150x30=450 cubic inches..
   or 12x12x30 - that's close too. 12x12=144*30= 144+144=288 + 144
   = 432 cubic inches. Again,, close enough. I have no idea what
   the 'right' answer is because most of the time, the perfect
   answer doesn't matter. unless the size of the *gap* matters. "