Well, in mathematics, 345 is known as a Pythagorean triple. A Pythagorean triple is three integer lengths which together make up the sides of a right-angle triangle. And just as with prime numbers, there’s an infinite number of Pythagorean triples, of which 345 is just the first and the best-known.
As you might imagine, they’re named after Pythagoras, the Greek mathematician from the 7th century BC, but they date back much further than that.
The earliest recorded Pythagorean triples are inscribed on clay tablets and you can find them in the British Museum. They date back from ancient Babylon 2000 BC!
It’s thought that when the Egyptians started building the pyramids, they didn’t even have the wheel. But they knew that 3, 4, and 5 will make a perfect right angle, and that’s what helped them build the most enduring structures the world has ever seen.
And that’s where we get the name 345 from!