Stonehenge secret: Did builders use Pythagoras' theorem 2,000 years before the philosopher lived?

The famous ancient site at Stonehenge may have been built using Greek philosopher Pythagoras’ famous theorem two millennia before the mathematical equation was developed, experts say.

Ooh, "experts." Should be good.

A new book titled “Megalith: Studies in Stone,” argues that the same geometric principles that framed Pythagoras’ famous work can be found at the prehistoric site. The book’s publication coincides with the Thursday’s summer solstice, which is closely associated with Stonehenge.

The World Heritage site is known for its alignment with the movements of the Sun - thousands travel to the site in Avebury, Southern England, to mark the solstices in Summer and Winter.

The first monument at the site, an early “henge” monument, was constructed about 5,000 years ago. The world-famous stone circle was built around 2,500 B.C. during the late Neolithic period.

What the heck are they talking about here? This:

Citing the book’s authors, The Telegraph reports that a rectangle of four Sarsen stones, or sandstone blocks, when split in half diagonally, forms a perfect Pythagorean 5:12:13 triangle. The Sarsen stones date to 2,750 B.C.

One of the book’s contributors, Robin Heath, also proposes the existence of a great Pythagorean triangle in the English landscape link Stonehenge, the site in Wales from which its bluestones were cut, and Lundy Island, a prehistoric site in England’s Bristol Channel.

But any rectangle if split in half diagonally will form 2 right triangles, which will by virtue of being right triangles obey the Pythagorean theorem. This seems highly dubious. Is there a precise rectangle formed by these 4 stones in the first place, or are they just saying "close enough"?

The other thing I can't even understand. "a great Pythagorean triangle in the English landscape link Stonehenge" What is "landscape link Stonehenge"? What does that mean?