The length of diagonal TD is 28, and the length of diagonal SN is 20.
Given that the segments TN = 14 and UN = 10 in parallelogram STUD, we can use the fact that diagonals of parallelograms bisect each other to find the diagonal TD and SN.
Since TN is a segment on the diagonal TD, we can use the fact that the diagonals bisect each other to determine that TD = 2 * TN = 2 * 14 = 28.
Similarly, since UN is a segment on the diagonal SN, we can use the same fact to determine that SN = 2 * UN = 2 * 10 = 20.