Let's call these consecutive angles x and y. Let x be the larger angle. We know two relationships between them:

x + y = 180 and x-y = 72

x-y = 72 ---> x = 72 + y: substitute this x value into the first equation.

72+y + y = 180

2y = 108

y = 54

x = 72 + y = 72 + 54 = 126

In a parallelogram opposite angles are congruent. So there are two angles that are 54 degrees, y and the angle opposite it, and there are two angles that are 126 degrees, x and the angle opposite it.