Question 964550
{{{A=(1/2)bh}}}
{{{56=(1/2)b(b-9)}}}
{{{b^2-9b=112}}}
{{{b^2-9b-112=0}}}
{{{(b+7)(b-16)=0}}}
Only positive solutions make sense here,
{{{b-16=0}}}
{{{b=16}}}
Then,
{{{h=16-9}}}
{{{h=7}}}