The area of a parallelogram is length × width.
Since you already know the area of the parallelogram, make an equation where you have the width but not the height, and length × width = 64 in².
The width of the parallelogram is shown on the diagram = 8 inches. You are missing the length = x. Your equation will look like:
x × 8 = 64, or 8x = 64. Solve for x to find the length of the parallelogram.
8x = 64
Divide both sides by 8 to isolate x.
x = 8
The missing length is 8 inches.