Answer: b = 5
Explanation:
Here parallelogram wxyz has diagonals,
4b-6 and 2b+4
Since, If a parallelogram has a equal pair of congruent or equal diagonal it is called a rectangle.
Thus, if wxyz is a rectangle,
Then, 4 b - 6 = 2 b + 4
⇒ 4b = 2 b + 4 + 6
⇒ 4 b = 2 b + 10
⇒ 4 b - 2 b = 10
⇒ 2 b = 10
⇒ b = 5
Hence, for b = 5, wxyz is a rectangle.