Investigation 1: The Coordinate Plane
Investigation 1: The Coordinate Plane is a Grade 8 introductory activity in Saxon Math Course 3, Chapter 1, where students explore the structure of the coordinate plane including the x-axis, y-axis, origin, four quadrants, and how to plot and identify ordered pairs. This investigation builds the spatial reasoning foundation required for graphing equations, transformations, and algebraic functions.
Key Concepts
New Concept Welcome to Math Course 1! This course connects arithmetic to geometry and algebra, showing how numbers can describe relationships and locations on a plane. What’s next To begin, we'll explore the coordinate plane—a key tool for visualizing math. Soon, you’ll analyze worked examples on plotting points and calculating area.
Common Questions
What is the coordinate plane?
The coordinate plane is a flat surface defined by two perpendicular number lines: the horizontal x-axis and the vertical y-axis. They intersect at the origin (0, 0) and divide the plane into four quadrants.
What are the four quadrants of the coordinate plane?
Quadrant I has positive x and positive y. Quadrant II has negative x and positive y. Quadrant III has negative x and negative y. Quadrant IV has positive x and negative y.
How do you plot an ordered pair on the coordinate plane?
Start at the origin, move horizontally by the x value, then vertically by the y value, and mark the point.
What is the origin of the coordinate plane?
The origin is the point (0, 0) where the x-axis and y-axis cross.
Where is the coordinate plane first explored in Grade 8?
The coordinate plane is introduced in Saxon Math Course 3, Chapter 1: Number and Operations and Measurement, through an investigation activity.