Question 307047
Since "the width is 3 times longer than the height, and the length is 9 times longer than the height", this means that {{{W=3H}}} and {{{L=9H}}}



{{{V=LWH}}} Start with the given volume formula.



{{{64=(9H)(3H)H}}} Plug in {{{V=64}}} (the given volume) {{{W=3H}}} and {{{L=9H}}}



{{{64=27H^3}}} Multiply



{{{64/27=H^3}}} Divide both sides by 27.



{{{root(3,64/27)=H}}} Take the cube root of both sides to isolate 'H'



{{{4/3=H}}} Take the cube root of {{{64/27}}} to get {{{4/3}}}



So the height is {{{H=4/3}}} ft. Simply plug this value into {{{W=3H}}} and {{{L=9H}}} to find the width and length respectively. I'll let you do this.