Teaching Notes 4.4: Graphing Ordered Pairs
on the Coordinate Plane
Graphing points on the coordinate plane is relatively easy for students, provided they remember
that they must move to the right or left before moving up or down on the graph. Some students,
however, require additional practice to rememberto move in the proper directions.- Review the coordinate plane with your students. Emphasize the following:
- A plane is a flat surface divided into four sections called ‘‘quadrants.’’
- The quadrants are formed by the intersection of a horizontal number line called thex-axis
and a vertical number line called they-axis. - The origin (0, 0) is the point where thex-axis andy-axis intersect.
- Explain that the coordinate plane can be used to graph ordered pairs. The graph of an ordered
pair is called a ‘‘point.’’ For (x,y), thex-coordinate indicates how many units to move right or
left along thex-axis. They-coordinate indicates how many units to move up or down along
they-axis. All movement begins at the origin. - Emphasize that order matters. (x,y) differs from (y,x). For example, point (2, 5) is not the
same point as point (5, 2). - Review the procedure for graphing ordered pairs on the worksheet with your students.
- Provide an example showing how (−3, 4) is graphed on the coordinate plane. Explain that
students must start at (0, 0), then move three units to the left, four units up, and finally
graph the point.
EXTRA HELP:
To graph (x,y), remember thatxis written beforey. Move horizontally before moving vertically.ANSWER KEY:
(1)E (2)B (3)J
(4)A (5)F (6)I
(7)H (8)C (9)D
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(Challenge)Yes, (x,y)=(y,x)butonlyifthex-coordinate is the same as they-coordinate.
------------------------------------------------------------------------------------------144 THE ALGEBRA TEACHER’S GUIDE