Two parallelograms, turn one of them into a rectangular plane figure we have learned, tell us how you spell it and write your operation process.

Draw a height line from an obtuse vertex of the parallelogram to the opposite side, cut along this height line, and translate the cut right triangle so that the hypotenuse of the right triangle is translated to coincide with the opposite side of the original parallelogram to obtain a rectangle;

Conclusion: The area of parallelogram is equal to the base times the height.