Math 6 H Periods 1, 6 & 7

Graphs of Ordered Pairs 11-8


The location of a desk in a classroom can be described as “ second row, third desk” If we write (2, 3) to represent this location, the order of the numbers is important since (3, 2) would represent “third row, second desk) a pair of numbers whose order is important is called an ordered pair. Remember when you first walked into our classroom on the very first day—You had to find your seat – and it was an ordered pair!!

We graph a number as a point on a number line. We graph an ordered pair of numbers as a point on a plane marked with two perpendicular number lines called axes. The first number of an ordered pair is associated with the horizontal number line—called the x- axis and the second number with the vertical number line, called the y axis. The axes meet in a point, called the origin (0, 0).

Open your books to Page 389 to review - we are looking at the top graph on that page. To locate the ordered pair (3,2) start at the origin—where is that?—go 3 units to the right and then 2 units up. The numbers 3 and 2 are the coordinates of the graph (3, 2) the plane itself is called a coordinate plane.
Remember (x, y) it is x first, then y. It is Horizontal first, then Vertical, Across and then Up/Down its easy to remember… each is alphabetically in order..