Question 1
Opposite sides of a parallelogram are congruent, so
.
Question 2
Opposite sides of a parallelogram are congruent, so
.
Question 3
Diagonals of a parallelogram bisect each other, so
.
Question 4
Adjacent angles of a parallelogram are supplementary, so
.
Question 5
Opposite angles of a parallelogram are congruent, so
.
Question 6
Adjacent angles of a parallelogram are supplementary, so
.