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There are many situations in which you might need to describe your position and direction of travel. For example, you may tell a friend that you will meet them on the corner, by the bus station, at 7pm, and that if they are late you will start walking up the high street. In mathematics, we use more precise ways to describe position and direction of travel.
Coordinates
The x axis is the horizontal axis.
The y axis is the vertical axis.
The origin is the point where the two axes cross - their point of intersection.
Remember that axes must always be labelled x and y.
Coordinates are written as a pair of numbers in round brackets. They are separated by a comma - for example:
(2, 3) (-1, 4) (17, 0).
The first number always refers to the x-coordinate.
The second number refers to the y-coordinate.
Now have a look at some sample exam questions:
- Question
What is the x-coordinate of the point (2, 7)?
- Answer
The x-coordinate is 2.
- Question
What is the y-coordinate of the point (3, 5)?
- Answer
The y-coordinate is 5.
We know that the first number is the x-coordinate. The x axis is horizontal, so the x-coordinate describes the horizontal position of the point.
We also know that the second number is the y-coordinate. The y axis is vertical, so the y-coordinate describes the vertical position of the point.
Example:
A is the point with coordinates (2, 1).
B is the point with coordinates (-1, -3).
- Question
Copy the grid onto squared paper.
Mark the points A (0, 3), B (3, 0), C (1, -2) and D (-2, 1).
Join A --> B --> C --> D --> A
What is the name of the quadrilateral ABCD?
- Answer
ABCD is a rectangle.
Did you get it right? If not, check that you have plotted the points correctly.
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