## OBJECTIVE: To graph points on the coordinate plane

A coordinate plane consists of a pair of lines (a horizontal line called the x-axis and a vertical line called the y-axis) that intersect at right angles at point (0, 0) called the origin. Every point on the coordinate plane is identified by an ordered pair of numbers (x, y) called coordinates. The first number is called the x-coordinate or abscissa, and the second number is called the y-coordinate or ordinate. The applet below dynamically illustrates how to graph ordered pairs on the coordinate plane. PRESS the New Example button. Then PRESS Plot Point. Carefully observe the arrow movements and note the coordinates of the point where the arrow stops. Repeat a few times until you get the concept.

QUESTION 1: You might have noticed that the first movement of the arrow in the dynamic illustration had always been horizontal. Do you think you'll get the same result if the first movement is vertical? Briefly explain.

## TRY IT YOURSELF ...

PRESS the New Problem button. Then plot the point shown on the top right corner of the applet by dragging the large white dot to the given coordinates. Click Check Answer. If your answer is correct, a large Correct! sign will appear. Repeat a few times until you get the concept. You can try different paths to get to your target point (horizontal then vertical, or vertical then horizontal, or even diagonal).

QUESTION 2: Among the different paths that you tried, which one did you find most convenient? Briefly explain.

## TODAY you observed a dynamic illustration of how to plot points. You also learned how to plot points without using the Toolbar.

In future lessons, you will learn how to plot points using the Toolbar.