Step-by-step explanation:
You haven't given us a diagram of your figure. Assume it is like the one in the image below.
The formula for the area of a parallelogram is
A = bh
1. Determine the height of the parallelogram
Notice that the angle is 45°. That makes the triangle an isosceles right triangle, so we can use Pythagoras' Theorem.
h² + h² = (6√2)²
2h² = 36 × 2 = 72
h² = 36
h = 6
2. Calculate the area of the parallelogram