Hi, how do I solve this one? ( help me :-( )

The sides of the base of a parallelepiped (not a right parallelrpiprd) are 4 cm and 10 cm, the distance between the lines containing the sides of the base is 8 cm. The side seam is equal to 4.2 cm. Find the diagonals of the parallelepiped.

Thank you♡​