Q: Marci wants to prove that the diagonals of
a rectangle are congruent. Which of these
procedures would be best for Marci to use
to write a correct proof?

a) She should use the fact that the
diagonals of a square are perpendicular
and then use the triangle-angle-sum
theorem.

b) She should use the fact that the
opposite sides of a parallelogram are
congruent and then use the
Pythagorean theorem.

c) She should use the fact that the
opposite angles of a parallelogram are
congruent and then use triangle
similarity relationships.

d) She should use the fact that the
diagonals of a parallelogram bisect the
angles of the parallelogram and then
use triangle congruence relationships.