Question 985307
b, base
h, altitude
b-h=4


Area is calculated just like a rectangle.


{{{b*h=71}}}
{{{(4-h)h=71}}}
{{{4h-h^2-71=0}}}
{{{highlight(h=(1+- sqrt(1-4*4(-71)))/(2*4))}}}  and you want the PLUS square root form.


{{{h=(1+sqrt(1137))/8}}}