6.which of the following statements is TRUE
a. opposite sides of a parallelogram are congruent
b. opposite angles in a parallelogram are complementary
c. the diagonals in a parallelogram are always perpendicular segments
d. any two consecutive angles of a parallelogram are congruent and acute
7. which of the following statements is TRUE?
a. the diagonals of a parallelogram are parallel
b. the diagonals of a parallelogram are always congruent
c. the diagonals of a parallelogram are bisectors of each other
d. the diagonals of a parallelogram are always perpendicular to each other​