Question 70608
Cut the length of the base in half, since the height bisects the base. Now you will have a triangle of a base of 3 units and a hypotenuse of 6 units. Now use pythagorean's theorem to find the height. 
<pre>
                    {{{h^2+3^2=6^2}}}
                    {{{h^2=36-9}}}
                    {{{h=sqrt(27)}}}
</pre>