Question 1180553


use the diagonal formula of a rectangular prism 

diagonal {{{d= sqrt(a^2 + h^2 + b^2)}}}

  if  {{{a=b=6}}} and {{{d=9}}}, we have

{{{9= sqrt(6^2 + h^2 + 6^2)}}}

{{{9= sqrt( h^2 + 72)}}}..........square both sides

{{{81= h^2 + 72}}}

{{{81-72= h^2 }}}

{{{9= h^2 }}}

{{{h=sqrt(9)}}}

{{{h=3m}}}