Signs tell the quadrant

The idea

Coordinates of points are of the form (+, +) in Quadrant I, (–, +) in Quadrant II, (–, –) in Quadrant III and (+, –) in Quadrant IV.

Left and up

A point lies to the left of the y-axis and above the x-axis.

What signs do you expect for its two numbers (x, y)?

• (+, +)
• (−, +)
• (−, −)
• (+, −)

Visit the quadrants

Move P into each of the four quadrants. The table fills in the signs of x and y.

Signs by quadrant

Coordinates of points are of the form (+, +) in Quadrant I, (−, +) in Quadrant II, (−, −) in Quadrant III and (+, −) in Quadrant IV.

Notes

(+, +) in Quadrant I · (−, +) in Quadrant II · (−, −) in Quadrant III · (+, −) in Quadrant IV.

Check yourself

In which quadrant does the point (−3, −7) lie?

Point S (3, −5) lies in which quadrant?

Which point lies in Quadrant II?

How many of these points lie in Quadrant I? (2, 5) · (−2, 5) · (3, 3) · (4, −1) · (6, 7)

Answer: 3

(2, 5), (3, 3) and (6, 7) are (+, +). That is 3 points.

• I. Quadrant I has (+, +). Both numbers here are negative.
• II. Quadrant II has (−, +). Here y is negative too.
• III — correct. Yes. (−, −) is Quadrant III.
• IV. Quadrant IV has (+, −). Here x is negative.
• I. In Quadrant I both numbers are positive. S has y = −5.
• II. Quadrant II has a negative x. S has x = 3.
• III. Quadrant III has two negative numbers. S has x = 3.
• IV — correct. Yes. (3, −5) is (+, −): Quadrant IV.
• (4, 3). (+, +) is Quadrant I.
• (−4, 3) — correct. Yes. (−, +) is Quadrant II.
• (−4, −3). (−, −) is Quadrant III.
• (4, −3). (+, −) is Quadrant IV.