Question 811184
For a triangle,
{{{area=base*height/2}}}
For the sail
{{{base=x}}}{{{yards}}}
{{{height=(2x-6)}}}{{{yards}}}
The area, in square yards is
{{{x(2x-6)/2=70}}}
{{{x(2x-6)=2*70}}}
{{{2x^2-6x=140}}}
{{{2x^2-6x-140=0}}}
{{{x^2-3x-70=0}}}
{{{(x-10)(x+7)=0}}}
The solutions to that equation are
{{{x=10}}} and {{{x=-7}}} , but {{{x=-7}}} cannot be the length, in yards, of the base of a sail. It should be a positive number.
So the base of the sail measures {{{highlight(x=10)}}}{{{yards}}} ,
and the height measures {{{2x-6=2*10-6=20-6=highlight(14)}}}{{{yards}}} .