So, You Need To Find The Length Of One Of The Sides. So, Lets Find It Using The Cubed Method. 10*10*10 = 1000, So It Can't Be 10. 5*5*5 = 125, So It Needs To Be Bigger. 7*7*7 = 343, So Bigger. 8*8*8 = 512, So Bigger. 9*9*9 = 729m^3, So, The Side Length Of The Cube Is 9 Meters. I Hope This Helps!