PRE-ALGEBRA

PRE-ALGEBRA

Lesson 1-10 Warm-Up

PRE-ALGEBRA

Lesson 1-10 Warm-Up

PRE-ALGEBRA

“The Coordinate Plane” (1-10)

What is the coordinate plane and how do you graph coordinates on it?

coordinate plane (also called a grid): two number lines that intersect (cross) at right angles

x-axis: the horizontal number line

y-axis: the vertical number line

origin (means “beginning”): the point at which the two number lines cross

quadrant (means “one of four parts”): one of the four sections made by the intersection of the two axes

ordered pair: two numbers called the x-coordinate and y-coordinate that that identify the location of a point on the coordinate plane

The x-coordinate tells you how far to move right (+) or left (-) from the origin and the y-coordinate tells you how far to move up (+) or down (-) from the origin.

PRE-ALGEBRA

Identify the coordinates of each point.

Point A is 2 units to the right of the y-axis. The x-coordinate is 2.

Point A is 3 units below the x-axis. The y-coordinate is –3.

The coordinates of point A are (2, –3).

b. B

Point B is 2 units to the left of the y-axis. The x-coordinate is –2.

Point B is 1 unit above the x-axis. The y-coordinate is 1.

The coordinates of Point B are (–2, 1).

a. A

The Coordinate PlaneLESSON 1-10

Additional Examples

PRE-ALGEBRA

Graph point P(–3, 2 ) on a coordinate plane.12

The Coordinate PlaneLESSON 1-10

Additional Examples

PRE-ALGEBRA

How do you name a point on a grid?

How do you graph a point on a grid?

Always start at the origin. Then, count the number of units (jumps) right (+) or left (-) to identify the x – coordinate. From there, count the number of units up (+) or down (-) from the x-axis to identify the y – coordinate

Example: Name the following coordinate.

Start at the origin. Move 2 units to the left (x = -2). Then move 3 units down (y = -3). The coordinates of z are (-2, -3)

Example:

“The Coordinate Plane” (1-10)

PRE-ALGEBRA

In which quadrant or on which axis would you find each point?

a. (5, 3)

Since the x-coordinate is positive and the y-coordinateis positive the point is in Quadrant I.

b. (0, –7)

Since the x-coordinate is 0, the point is on the y-axis.

The Coordinate Plane LESSON 1-10

Additional Examples

PRE-ALGEBRA

Plot and label each point on a coordinate plane. Connect the points with lines.

The figure is a rectangle.

Graph a figure with vertices M(–3, 3), N(–3, –2),

P(1, 3), and R(1, –2). Name the figure.

The Coordinate PlaneLESSON 1-10

Additional Examples

PRE-ALGEBRA

Draw a coordinate grid. Graph each point.

1. S(2, 3) 2. T(2, –3)

3. U(–2, 3) 4. K(0, –3)

5. L(3, 0) 6. Graph a figure with vertices A(–1, 4), B(3, 4), C(2, –1) and, D(0, –1), Name the figure.

Lesson Quiz

LESSON 1-10

The Coordinate Plane

1–5