You need to know the angles too. And then you have to apply some trigonometry: So there you go: the area of a parallelogram is a · b · sin α. Greek letters! Blecch. So sure, respect the ...

Save guides, add subjects and pick up where you left off with your BBC account. Showing that a parallelogram has the same area as a rectangle: Split the parallelogram into a right-angled triangle ...

Resolving this unusual parallelogram structure has helped astronomers finally put together a picture of its history. The geometric shape can be explained using a model that describes a flat spiral ...

“It is slightly a parallelogram,” says Dash, and this suggests its builders were better at measuring precise distances than they were at measuring precise right angles. “We think they were ...