Question 1065054
Triangle area,  {{{(1/2)*b*h}}}  for base b and height h.
{{{b=h+3}}}, according to problem description.


{{{(1/2)(h+3)h=20}}}


{{{h^2+3h=40}}}


{{{h^2+3h-40=0}}}


{{{(h-5)(h+8)=0}}}

The choice that makes sense is {{{highlight(h=5)}}}.