Question 1114432
{{{(3x)(5x)(9x)=8640}}}
{{{x^3=64}}}
{{{x=4}}}
So the width, height, and length are,
{{{W=3*4=12}}}
{{{H=5*4=20}}}
{{{L=9*4=36}}}
The surface area of the prism is,
{{{SA=2*L*H+2*L*W+2*W*H}}}
{{{SA=2*36*20+2*36*12+2*12*20}}}
Work that out for the answer in {{{mm^2}}}