9-1 Ordered Pairs Presented by Mrs. Spitz Fall 2006

Objective After studying this lesson, you should be able to graph ordered pairs on a coordinate plane. After studying this lesson, you should be able to graph ordered pairs on a coordinate plane.

Assignment pg. 357 #5-57 all pg. 357 #5-57 all

Application Mrs. Spitz makes seating charts for her classes. Her classroom has 4 rows of desks with 7 desks in each row. She assigns desks by using two numbers. The first number is for the row of the desk and the second number is for the desk in that row. Mrs. Spitz assigns (3, 2) to Christina and (2, 3) to Jasmine. This means Christina will sit in the third row at the second seat and Jasmine will sit in row 2 at the third seat. Mrs. Spitz makes seating charts for her classes. Her classroom has 4 rows of desks with 7 desks in each row. She assigns desks by using two numbers. The first number is for the row of the desk and the second number is for the desk in that row. Mrs. Spitz assigns (3, 2) to Christina and (2, 3) to Jasmine. This means Christina will sit in the third row at the second seat and Jasmine will sit in row 2 at the third seat.

Graphic Jasmine Christina

Notice that (3,2) and (2, 3) do not name the same desk in the seating chart. (3,2) and (2,3) are called ordered pairs because the order in which the pairs are written is important. Notice that (3,2) and (2, 3) do not name the same desk in the seating chart. (3,2) and (2,3) are called ordered pairs because the order in which the pairs are written is important. Ordered pairs are used to locate points in a plane. The points are in reference to two perpendicular lines at which the number lines intersect called the ORIGIN Ordered pairs are used to locate points in a plane. The points are in reference to two perpendicular lines at which the number lines intersect called the ORIGIN

Some definitions Perpendicular lines are lines that meet to form 90º angles. Perpendicular lines are lines that meet to form 90º angles. Origin—the point where the X-axis and y- axis meet (0,0). Origin—the point where the X-axis and y- axis meet (0,0). X-axis—the horizontal axis X-axis—the horizontal axis Y-axis—the vertical axis Y-axis—the vertical axis Coordinate plane—the plan that contains the x and y axis Coordinate plane—the plan that contains the x and y axis

Some more information The first number, or coordinate, or an ordered pair corresponds to a number on the x-axis. The second number of an ordered pairs, corresponds to the y axis. To find the ordered pair for A, shown in the next graphic, thnk of a horizontal and a vertical line passing through point A. The first number, or coordinate, or an ordered pair corresponds to a number on the x-axis. The second number of an ordered pairs, corresponds to the y axis. To find the ordered pair for A, shown in the next graphic, thnk of a horizontal and a vertical line passing through point A.

Points on a Coordinate Plane The coordinate plane is divided into 4 quadrants The coordinate plane is divided into 4 quadrants Each quadrant has the first number either positive or negative as well as the second positive or negative. Look to see which is which. Each quadrant has the first number either positive or negative as well as the second positive or negative. Look to see which is which. Quadrant I (+,+) Quadrant II (-, +) Quadrant III (-, -) Quadrant IV (+, -)

Points on a Coordinate Plane Imagine a the origin (0,0). Now draw a point that is at (-2.-3) and (3, 2) Imagine a the origin (0,0). Now draw a point that is at (-2.-3) and (3, 2) Where is point A located? Point B? Point C? Point D? Where is point A located? Point B? Point C? Point D? CA D B

Points on a Coordinate Plane Plot the following point—(3,1) Plot the following point—(3,1) Start at the origin (0,0) and move 3 units to the right. Then move one unit up and draw a dot. Label this E. Start at the origin (0,0) and move 3 units to the right. Then move one unit up and draw a dot. Label this E. CA D B

Points on a Coordinate Plane Plot the following point—(3,1) Plot the following point—(3,1) Start at the origin (0,0) and move 3 units to the right. Then move one unit up and draw a dot. Label this E. Start at the origin (0,0) and move 3 units to the right. Then move one unit up and draw a dot. Label this E. CA E D B

Points on a Coordinate Plane Plot the following point—(-3,-2) Plot the following point—(-3,-2) Start at the origin (0,0) and move 3 units to the left since it’s negative. Then move one unit down and draw a dot. Label this F. Start at the origin (0,0) and move 3 units to the left since it’s negative. Then move one unit down and draw a dot. Label this F. CA D B

Points on a Coordinate Plane Plot the following point—(-3,-2) Plot the following point—(-3,-2) Start at the origin (0,0) and move 3 units to the left since it’s negative. Then move one unit down and draw a dot. Label this F. Start at the origin (0,0) and move 3 units to the left since it’s negative. Then move one unit down and draw a dot. Label this F. CA FD B

Completeness Property for Points in a Plan 1. Exactly one point in a plane is named by a given ordered pair of numbers. 2. Exactly one ordered pair of numbers names a given point in a plane.

You need: Graph paper Graph paper Ruler /straight edge Ruler /straight edge colored pencil (to mark different lines) colored pencil (to mark different lines) Go to Departments|Math for graph paper that is already lined and made up. I won’t provide it unless it’s easy. You go print it. Go to Departments|Math for graph paper that is already lined and made up. I won’t provide it unless it’s easy. You go print it.