73.5 sq. cm
Sides = x and y Diagonal = SQRT(x^2+y^2)=23 ---> (1) Perimeter = 2*(x+y)=52 ---> x+y=26 (2) Area= xy=?
(1) --> x^2+y^2=23^2=529 (2) --> (x+y)^2=26^2 --> x^2+y^2 +2xy=676 --> considering (1) 529 + 2xy=676 --> xy=(676-529)/2=73.5