Question 865450
Lawn PLUS the path around it, {{{(9+2w)(10+2w)}}}, using w for the width of the path.


Total Area - Lawn Area = Path Area
{{{highlight_green((2w+9)(2w+10)-9*10=120)}}}.
{{{4w^2+18w+20w+90-90-120=0}}}
{{{4w^2+38w-120=0}}}
{{{2w^2+19w-60=0}}}
-
{{{Discr=19^2-4*2(-60)=19^2+8*60=19^2+480=841=29^2}}}
-
{{{w=(-19+sqrt(Discr))/4=(-19+sqrt(29^2))/4=(-19+29)/4}}}
{{{w=10/4=5/2}}}
{{{highlight(w=2&1/2)}}} feet.