Question 903541
w = width of the uniform path around pool


{{{highlight_green((8+2w)(12+2w)-8*12=189)}}}
{{{8*12+24w+16w+4w^2-8*12=189}}}
{{{4w^2+40w-189=0}}}


{{{w=(-40+sqrt(1600+4*4*189))/(2*4)}}}
{{{w=(-40+4sqrt(289))/(2*4)}}}
{{{w=(-10+sqrt(289))/2}}}
{{{w=(17-10)/2}}}
{{{highlight(w=7/2)}}}