What is the world’s oldest example of applied geometry?

It's a 3700-year-old clay known as Si.427.

A UNSW mathematician has revealed the origins of applied geometry on a 3700-year-old clay tablet that has been hiding in plain sight in a museum in Istanbul for over a century.

The tablet – known as Si.427 – was discovered in the late 19th century in what is now central Iraq,

This is a significant object because the surveyor uses what are now known as “Pythagorean triples” to make accurate right angles.