A parallelogram has a base of 8 centimetres and a perpendicular height of 5 centimetres. What is its area?

Explanation

A parallelogram can be cut and rearranged into a rectangle with the same base and perpendicular height, so its area is simply 8 times 5. Halving that product borrows a step that belongs to triangles, and a parallelogram covers twice what the triangle on the same base does.