Which of the following is not a property of a parallelogram?

  Consecutive sides are complementary

Step-by-step explanation:

"Complementary" is an attribute of angles, not of sides. The statement is nonsense, so is not a property of parallelograms (or anything else).

ok then what happened.

step-by-step explanation:

the true statements are:

r = set of real numbers

n = set of natural numbers, 1,2,

w = n u{0} = {0,1,}