For hundreds of years man has been studying Geometry. Ancient civilizations like the Egyptians and the Babylonians discovered many properties through actual measurements. However it is the 3 Greek mathematician Euclid who is credited with giving a completely new outlook to the study of Geometry. He showed that all knowledge is not arrived at by physical measurements. If some basic facts that seem simple and obvious are accepted as true the remaining facts can be arrived at by logical reasoning. Those facts which, are to be simply accepted are called 'axioms' and those which can be questioned or proved are called 'theorems.'