History of mathematical notation back to any school or period before that of the Ionian Greeks, but the subsequent history may be divided into periods, the distinctions between which are tolerably well marked. Greek mathematics, which originated with the study of geometry, tended from its commencement to be deductive and scientific. Since the fourth century AD, Pythagoras has commonly been given credit for discovering the Pythagorean theorem, a theorem in geometry that states that in a right-angled triangle the area of the square on the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares of
Jessie (given name) Jessie (given name) Jessie is a given name in its own right, but may also be a nickname for the given name Jessica. It is generally considered the feminine form of Jesse. The name Jess is also a given name. It, or Jesse, may be used in Spanish as a nickname for the male name Jesus. In Celtic usage, Jessie is not related to Jessica. It is considered a pet form of the name Jane or Jean (feminisations of John). This is expressed in Gaelic variants as the names Seana/Seóna (Shawna) or Sìne (Sheena). Related feminine names taken from John