In the following figure, if AO = 4 cm, then the length of the diagonal AC is _____.
8 cm
We know that the diagonals of a parallelogram bisect each other.
So, diagonal BD bisects the diagonal AC. (Also, diagonal AC bisects the diagonal BD)
Therefore AO = OC.
Given AO = 4 cm
Hence, OC = 4 cm
Now, AC = AO + OC = 4 cm + 4 cm = 8 cm.