Diagonal of a Quadrilateral
Geometry · 25th PMO Qualifying Stage
The sides of a convex quadrilateral have lengths $12$ cm, $12$ cm, $16$ cm, and $16$ cm, and they are arranged so that there are no pairs of parallel sides. If one of the diagonals is $20$ cm long, and the length of the other diagonal is a rational number, what is the length of the other diagonal?
A$\frac{48}{5}$ cm
B$\frac{84}{5}$ cm
C$\frac{96}{5}$ cm
D$\frac{108}{5}$ cm