So before we can solve for the area, we need to find the height of the parallelogram. And as we see before us, there is a triangle within this parallelogram. However, this is considered a special triangle. The 45-45-90 triangle states that if the legs are x, then the hypotenuse is x√2.
In this case, since the hypotenuse is 18√2 units, the legs are 18 units.
Now remember that the area of the parallelogram is the same as the rectangle; A = bh (b = base, h = height). Now that we have both height, 18, and our base, 28, we can solve for the area.
Our equation looks like this: A = 18(28)
For this, all you need to is multiply, and your answer will be A = 504 un^2.