Plot and recognise horizontal and vertical lines

Home learning focus

It is the second day of coordinates week! Today you will learn how to use coordinates to draw horizontal and vertical lines.

Go to yesterday's lesson for a refresher on plotting coordinates.

This lesson includes:

  • a learning summary
  • two activities

Learn

Horizontal and vertical lines (in the form y = c and x = c)

Plotted points on a graph are referred to as coordinates.

Coordinates are a pair of numbers written in the form (x, y) where x is the amount moved horizontally, and y the amount moved vertically from the origin (0, 0) on a graph. The two values are referred to, in order, as the x-coordinate and the y-coordinate.

Graphs of the form y = c and x = c, will either be a horizontal or vertical line.

y = 4

The graph shows the line y = 4.

This means the y cordinate is always at 4, regardless of where the x corordinate is. This means y = 4 is a straight, horizontal line.

x = -2

This graph shows x = -2.

This is a straight, vertical line because the x-coordinate does not change, it is always at -2.

Top tip

If you are unsure whether the equation of the line is of the form x = c or y = c, find the coordinates of at least two points on the line.

If the x-coordinates are the same, the equation of the line will be of the form x = c, where c is the x-coordinate.

If the y-coordinates are the same, the equation of the line will be of the form y = c, where c is the y-coordinate.

Practise

Activity 1

Equations of horizontal and vertical lines

Try this activity from Teachit. Write down your answers on paper and check them yourself - the answers are at the bottom of the worksheet.

Equations of horizontal and vertical lines worksheet

Activity 2

Reflecting one point

Now try this activity from Teachit. Print out the activity or draw the coordinates on squared paper - there might be some in your Maths workbook from school.

The answers are at the bottom of the worksheet.

Reflecting one point

There's more to learn

Have a look at these other resources around the BBC and the web.

KS3 Maths
BBC Bitesize Daily
Bitesize Support
11-14 Maths
Jekyll and Hyde
Radio 1's Movie Mixtapes