The probability is 0. Fair dice have six sides, and each side has an equal chance of being rolled. The maximum possible outcome with two dice is 6 + 6 = 12, rendering a total of 13 unattainable. Hence, the probability of achieving a total of 13 is 0.
The characterization of HIJK as a parallelogram arises from the fact that the midpoints of both diagonals coincide at (1, 0), which indicates that these diagonals bisect each other. To explicitly demonstrate this, we determine that the midpoints of the diagonals HJ and IK are equal, confirming HIJK's properties as a parallelogram.