2t° = 18° because they are alternate angles ==> t = 9
4r = 18 because it is a parallelogram ==> r = 18/4 = 4.5 ==> r = 4.5
8s = 7s + 3 because the diagonals on a parallelogram bisect each other
solving for s:
8s - 7s = 3
s = 3
Answer:
t = 9
r = 4.5
s = 3