1) The supplement of 72° is 180°-72° = 108° . (bottom // with right secant)
2) (3z + 18)° = 108° ( in a para llelogram opposite angles are equal)
Then 3z+18 = 108 and 3z° = 90° → z = 30°
3) (3y)° = 108° (vertical angles) , 3y° = 108 and y = 36°
4) 3y = x° (corresponding angles) but 3y = 108, then x = 108°
(Mind you I am calculating the ∠ x, y, and z. To find the angles of the parallelogram replace x,y and z by their respective values