The base and perpendicular height are at right angles. Showing that a parallelogram has the same area as a rectangle: Split the parallelogram into a right-angled triangle and a trapezium. Move the ...

Quite so. The problem with parallelograms is that they’re a con. They tell you that finding the area is simple: it’s base · height. Easy peasy! But what’s the height? Crap. The length of the sides isn ...