Fundamentals of Math

Fundamentals of Mathematics

A point in a coordinate plane is named by an ordered pair , ( , ) . The first number corresponds to the -coordinates and the second to the -coordinate. The -coordinate controls the horizontal direction, left if it is negative, and right if it is positive. The -coordinate controls the vertical direction, down if its negative, and up if it is positive. It is thus making the combination of signs unique to each quadrant. To plot a point, start at the origin and thenmove left or right units as indicated by the -coordinate, and then move down or up units as indicated by the -coordinate.

Example 4.1.1

Plot the point (3,4) .

1. Start at the origin.

2. Count over 3 units to the right. ( = 3)

3. Count over 4 units up. ( = 4)

4. Plot your point.

Example 4.1.2

What is the ordered pair for point ?

1. Locate the vertical line crossing through – this is this value is the -coordinate.

2. Locate the horizontal line crossing through – this is the -coordinate.

3. Write your ordered pair ( , ) → (−5,2)

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