The idea that position could be identified by ordered pairs of numbers on a set of crossed number lines is thought to have been 'discovered' by Rene Descartes in the early 1600's. Apparently he thought of it while watching a fly crawl around on ceiling tiles. He identified the location of a point on a flat suface using two numbers, written as an ordered pair (x , y) where the x number determined right/left position, and the y number up/down position. For example, the point (3 , -5) would be located three to the right and 5 down. Let's see how good you are at identifying points located this way. Below is a Cartesian coordinate system with some points located on it. Identify each of the points, and then check your answers below. Enter the points with brackets and a comma between: for example,   (-5 , 3) Point A:      Point B:      Point C: Point D:      Point E:      Point F: Point G:      Point H:      Point I : Point J:       The centre point: Scroll down for the answers. Don't peek until you're done! ANSWERS: A: (2, 4)     B: (4, 1)     C: (0, 2)     D: (-5, 3)    E: (-3, 0)    F: (-2, -4) G: (-6, -1)    H: (0, -2)    I: (4, -2) J: (6, 0)    centre (0, 0) BACK