Question 102316
The area of a triangle is {{{bh/2}}} where b is the base and h is the height. 
You state that {{{b=h/3}}} and that the area equals {{{24 m^2}}}.
Then
{{{bh/2=24}}}
{{{(h/3)h/2=24}}} Substitute for b.
{{{(h^2)/6=24}}} Simplify. 
{{{cross(6)h^2/cross(6) = 6*24}}}Multiplicative inverse of 6. 
{{{h^2=144}}} Simplify.
{{{h=12 m}}}
{{{b=h/3}}}
{{{b=12/3}}}
{{{b=4 m}}}