EDEXCEL GCSE FOUNDATION MATHS - What are Coordinates

Edexcel GCSE Foundation Maths: What are Coordinates?

Introduction

Coordinates are a way of describing the exact position of a point on a grid. They are used in many areas of maths, including graphs and maps.

The Coordinate Plane

The coordinate plane is a two-dimensional plane formed by two perpendicular lines, called the x-axis and the y-axis.

• X-axis: This is the horizontal line. Values to the right of the origin (where the axes intersect) are positive, while values to the left are negative.
• Y-axis: This is the vertical line. Values above the origin are positive, while values below are negative.

The point where the x-axis and y-axis intersect is called the origin and has the coordinates (0, 0).

Coordinates of a Point

Each point on the coordinate plane is defined by two numbers, called its coordinates. These coordinates are written in the form (x, y), where:

• x represents the point's horizontal position (its distance along the x-axis from the origin).
• y represents the point's vertical position (its distance along the y-axis from the origin).

Example: The point (3, 2) is located 3 units to the right of the origin and 2 units above the origin.

Plotting Points

To plot a point on the coordinate plane, follow these steps:

1. Start at the origin.
2. Move horizontally along the x-axis the number of units indicated by the x-coordinate. Move right for positive x-values and left for negative x-values.
3. Move vertically along the y-axis the number of units indicated by the y-coordinate. Move up for positive y-values and down for negative y-values.
4. Mark the point where you end up.

Example

Let's plot the points A (2, 3), B (-1, 4), and C (-3, -2).

       ^
       |
       |       C (-3, -2)
       |
   B (-1, 4)
       |
       |
-------+-------->
       |
       | A (2, 3)
       |
       |
       V

Key Points to Remember

• Coordinates are written in the form (x, y).
• The first coordinate (x) indicates horizontal position.
• The second coordinate (y) indicates vertical position.
• The origin has coordinates (0, 0).

Practice

Try plotting these points on a coordinate plane:

• (1, 1)
• (-2, 3)
• (0, -4)
• (5, 0)

By understanding coordinates, you'll be able to grasp many other concepts in Edexcel GCSE Foundation Maths, such as graphing equations and solving geometric problems.