JMATHSLEARNING

Point     A point is an exact location.                              A fine dot represents a point.                             It is denoted by capital letter – A, B, P, Q, etc. In the given figure, P is a point. Line Segment   The straight path between two points A and B is called the line segment  AB The points A and B are called the end points of the line segment  AB  .   A line segment has a definite length.                                                         Ray  A portion of a line which starts at a point and goes off in a particular direction to infinity is known as ray. Ray has one end point A. A Ray has no definite length. We write a ray  Line  A line segment  when extended indefinitely in both the directions is called the line . A line has no end points. A line has no definite length.  It is denoted by small letters l, m, n, etc. Incidence Axioms on lines     A line contains infinitely many points.

History Thales (640 BC – 546 BC) The word ‘Geometry’ is derived from the Greek words ‘Geo’ means ‘Earth’ and ‘Metrein’ means to ‘ To Measure’. A Greek mathematician, Thales is credited with giving the first known proof. This proof was of the statement that a circle is bisected (i.e., cut into two equal parts) by its diameter. One of Thales’ most famous pupils was Pythagoras (572 BC), whom you have heard about. Pythagoras and his group discovered many geometric properties and developed the theory of geometry to a great extent. This process continued till 300 BC. At that time Euclid, a teacher of mathematics at Alexandria in Egypt, collected all the known work and arranged it in his famous treatise, Euclid  (325 BC – 265 BC) called ‘Elements’.          He divided the ‘Elements’ into thirteen chapters, each called a book. These books influenced the whole world’s understanding of geometry for generations to come. Euclid listed 23 definition in book 1 of the ‘Elements’. A