9A | Coordinate Plane Study Guide

Unit 7: Integers & Coordinate Plane • Lesson 7.5 • Standard: 6.NOS.7, 6.NOS.6b

Key Vocabulary

Coordinate Plane — a flat surface formed by two number lines that cross at a right angle. (plano de coordenadas)
X-axis — the horizontal (left-right) number line. (eje x)
Y-axis — the vertical (up-down) number line. (eje y)
Origin — the point where the x-axis and y-axis cross, at (0, 0). (origen)
Ordered Pair — two numbers (x, y) that name a point on the coordinate plane. (par ordenado)
Quadrant — one of four sections of the coordinate plane. (cuadrante)

Visual — The Four Quadrants

              y-axis
                |
     II         |        I
   (−, +)       |      (+, +)
                |
  ——————————(0,0)————————— x-axis
                |
    III         |       IV
   (−, −)       |      (+, −)
                |
Quadrant I: x is positive, y is positive (+, +)
Quadrant II: x is negative, y is positive (−, +)
Quadrant III: x is negative, y is negative (−, −)
Quadrant IV: x is positive, y is negative (+, −)

Step-by-Step: Plotting a Point

  1. 1 Start at the origin (0, 0).
  2. 2 Move left or right for the x-value (first number). Positive = right, Negative = left.
  3. 3 Move up or down for the y-value (second number). Positive = up, Negative = down.
  4. 4 Mark the point and label it with the ordered pair.
Example: Plot (3, −2)
Start at (0, 0) → move RIGHT 3 → move DOWN 2 → mark the point.
This point is in Quadrant IV.

Watch Out!

Practice Problems

1. What is the name of the point (0, 0)?

2. In which quadrant is the point (4, 3)?
Type a Roman numeral: I, II, III, or IV.

3. In which quadrant is the point (−5, −2)?
Type a Roman numeral: I, II, III, or IV.

4. To plot (−3, 5), you start at the origin, move LEFT 3 and then move _____. Type "up 5" or "down 5".