Question 426491
Solution:Denote x the height of triangle. We know that the area of triangle is:

  {{{A=(b*h)/2}}} Solve this literal equation with respect to b :

   {{{2*A=b*h}}}

   {{{b=(2*A)/h}}}. Substitute A=20 and h=x and we have:

    {{{ b=(2*20)/x}}} Now we write the equation:

   {{{x-(2*20)/x=3}}} Solve this equation:

   {{{x^2-3x-40=0}}} There are two roots {-13,5}.

 We reject the root -13 because the dimensions are always positive integers.

Answer: The base of triangle is 5 (units: m, cm, feet)