# 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.

## 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.

# There's more to learn

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