Question 155486
10*64=640 FT^2 FOR THE PATIO.
2X+Y=80 FOR THE PERIMETER.
XY=640
Y=640/X
2X+640/X=80
(2X^2+640)/X=80
2X^2+640=80X
2X^2-80X+640=0
2(X^2-40X+320)=0
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
X=(40+-SQRT[-40^2-4*1*320])/2*1
X=(40+-SQRT1600-1280])/2
X=(40+-SQRT320)/2
X=(40+-17.89)/2
X=(40+17.89)/2
X=57.89/2
X=28.945 FT. ANSWER.
2*28.945+Y=80
57.89+Y=80
Y=80-57.89
Y=22.11 FT. ANSWER.
DIMENTIONS FOR THE WALL ARE:2 WALLS=28.945 FT. EACH & THE THIRD WALL IS 22.11 FT.
PROOF:
28.945*22.11=640
640=640