When were triangle invented?

Triangles as a geometric concept have existed since ancient times, with their properties being studied by mathematicians in various cultures, including ancient Egyptians and Greeks. The Word "triangle" comes from the Latin "triangulus," meaning "three corners." While the concept of a triangle was understood thousands of years ago, formalizing the study of triangles and their properties, known as trigonometry, developed significantly in Greek mathematics around 300 BCE with figures like Euclid and later Ptolemy.