To find the diagonals we use the pythagorean theorem:
in each case the diagonal is the hypotenuse of the triangle.
For the base diagonal we have that the legs of the triangle are l and w, then we have:
Therefore the base diagonal is 9.9
Now, the second diagonal is the hypotenuse of the triangle with legs h and base diagonal, then we have that:
Therefore the second diagonal is 11.5