This example demonstrates how the area of a parallelogram formula can be derived using the formulas for the area of a rectangle.

- Start by observing that a parallelogram’s area can be divided into a rectangle and two triangles. This is shown in the illustration below.
- Then observe that the triangles can be rearranged by sliding one triangle underneath the other triangle
Finally, observe that the shape we are left with is the shape of a rectangle and from the area of a rectangle formula, we can conclude that the area of a parallelogram is equal to the base multiplied by the height.