The point whose coordinates are (2, 3) is located in the first quadrant or
QI, since both coordinates are positive. The point whose coordinates are
(4, 1) is located in the second quadrant or QII, since the x coordinate is
negative and the y coordinate is positive. The point whose coordinates are
(3,5) is in the third quadrant or QIII, since both coordinates are negative.
The point (3, 1) is located in the fourth quadrant or QIV, since the x
coordinate is positive and the y coordinate is negative (see Fig. 11-3).
The coordinates of the origin are (0, 0).
Any point whose y coordinate is zero is located on the x axis. For example,
point P, whose coordinates are (3, 0), is located on the x axis 3 units to the
left of the y axis. Any point whose x coordinate is zero is located on the y
axis. For example, the point Q, whose coordinates are (0, 4), is located on the
y axis four units above the x axis (see Fig. 11-4).
EXAMPLE
Give the coordinates of each point shown in Fig. 11-5.
SOLUTION
A(2, 4); B (3, 1); C (1,5); D (6,2); E (2, 0); F (0,4).
CHAPTER 11 Graphing 205
Fig. 11-3.