Final answer:
The length of the other diagonal in the parallelogram is approximately 34.64 cm.
Step-by-step explanation:
In a parallelogram, the diagonals bisect each other, meaning they divide each other into two equal segments. Let's call the length of the second diagonal x cm.
Given that the adjacent sides of the parallelogram are 30 cm and 20 cm, we can form a right triangle using one of the adjacent sides and one of the diagonals. By using the Pythagorean theorem, we can find the length of the other diagonal.
Using the 30-20-40 right triangle, we have:
202 + x2 = 402
400 + x2 = 1600
x2 = 1200
x = √1200 ≈ 34.64 cm
Therefore, the length of the other diagonal is approximately 34.64 cm.