In a convex quadrilateral (in the plane) with the area of the sum of two opposite sides and a diagonal is . Determine all the possible values that the other diagonal can have.
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In a convex quadrilateral (in the plane) with the area of $32 \text{ cm}^{2}$ the sum of two opposite sides and a diagonal is $16 \text{ cm}$. Determine all the possible values that the other diagonal can have.
Source: Međunarodna matematička olimpijada, shortlist 1976
Školjka 
the sum of two opposite sides and a diagonal is 
. Determine all the possible values that the other diagonal can have.