Mathematician:Heron of Alexandria

Mathematician
Heron (or Hero) of Alexandria (Greek: Ἥρων ὁ Ἀλεξανδρεύς) was a Greek mathematician and engineer.

Famous for writing about the, otherwise known as Hero's Engine (although he didn't actually invent it), and the device known as.

Also noted for Heron's formula for calculating the area of a triangle whose side lengths are known.

Nationality
Greek

History

 * Born: c. 10 CE, possibly in Alexandria, Egypt
 * Died: c. 70 CE

For a long time it was not certain whether Heron had lived in the 1st century BCE or CE, until noticed in $1938$ that he had described an eclipse of the moon such that it had to correspond with a particular lunar eclipse in 62 AD. Hence the question was settled.

Theorems and Definitions

 * Heron's Formula
 * Heron's Principle of Reflection
 * Hero's Method


 * Heronian Triangle
 * Fleenor-Heronian Triangle (with )
 * Heronian Mean

Publications

 * Pneumatica: on machines working on air.
 * Automata: on machines for performing so-called wonders in temples.
 * Mechanica: on methods of lifting heavy objects.
 * Metrica: calculation of surfaces and volumes of various objects.
 * On the Dioptra: on methods to measure lengths.
 * Belopoeica: on war machines.
 * : on the behaviour of light.

These works have at times been attributed to Hero, but the current belief is that they were most likely been written by someone else:
 * Geometria: equations based on the first chapter of Metrica.
 * Stereometrica: three dimensional calculations based on the second chapter of Metrica.
 * Mensurae: tools for making measurements based on Stereometrica and Metrica.
 * Cheirobalistra: on catapults.
 * Definitiones: definitions of terms for geometry -- this may have been written by.

These works exist only in fragments:
 * Geodesia
 * Geoponica

He is also supposed to have written a commentary on.

Also known as
Heron and Hero are equally often encountered.