Reading Off Graphs

Reading Off Graphs

KS3AQAEdexcelOCRWJEC

Reading off Graphs

Being able to read off graphs is an important skill. Luckily, it is relatively simple and if you know the method it can be an easy way to collect marks in an exam.

How to Read off Graphs

Reading off graphs is a fundamental skill – it allows us to convert between values without having to perform complicated calculations. Providing the graph features a line (as opposed to individual points, such as in a scatter graph), we can perform conversions using the following three steps:

  1. Identify the variable on one axis
  2. Draw a straight line from the axis towards the graph
  3. When the straight line crosses the graph, draw another line to the other axis and identify the value of the other variable

Example: Use the graph on the right to find the value of y when x=3

 

Following the steps above, we need to first go to the position of 3 on the x-axis (horizontal axis).

Next, we need to draw a straight line upwards to the graph.

When we hit the line of the graph, draw a horizontal line across to the y-axis (vertical axis).

As can be seen, the value on the y-axis is 4.5, so when x=3, y=4.5

reading of a straight line graphLevel 1-3GCSEKS3AQAEdexcelOCRWJEC

Example: Conversion Graphs

The conversion graph on the right can be used to convert distances between miles and kilometres. Use the conversion graph to convert the following:

a) 5 miles into kilometres

 

b) 10 kilometres into miles

[2 marks]

reading from conversion graph
reading from conversion graph

a) Identify the position of 5 miles on the horizontal axis. Next, draw a straight line upwards to the line of the graph, then draw a horizontal line from the graph to the vertical axis. As shown in the image on the right, 5 miles is equivalent to 8 kilometres.

 

b) Identify the position of 10 kilometres on the vertical axis. Draw a straight line across to the line of the graph, then draw a vertical line downwards to the horizontal axis. As shown in the image on the right, 10 km is equivalent to 6.2 miles.

Level 1-3GCSEKS3AQAEdexcelOCRWJEC

Note:

Reading off graphs is a simple skill, but make sure to read the question carefully. Students often make the mistake of reading from the wrong axis!

Example Questions

Draw a line from 12 lbs on the vertical axis to the graph. Draw a second line down from the graph to the horizontal axis:

As shown in the graph, 12 lbs is equivalent to 5.4 kg.

Go to the value of x=4 on the horizontal (x) axis and draw a straight line up to the graph. Where the straight line meets the curve, draw a horizontal line across to the vertical (y) axis.

reading from a curved graph

As shown in the graph above, y=1.6 when x=4

a) 0\degreeC is the beginning of the scale on the horizontal axis. At this point, the temperature in Fahrenheit is 32\degreeF

 

b) Draw a horizontal line across from 95\degree to the line of the graph. Draw a vertical line down from the graph to the horizontal axis.

As shown on the graph, 95\degreeF is equivalent to 35\degreeC

a) Draw a vertical line up from x=2 to the graph. Then draw a straight line across to the y-axis. When x=2, y=2

 

b) Draw a horizontal line across from y=6 to the graph. Then draw a vertical line down to the x-axis. When y=6, x=4

cubic graph answer

This graph has an unusual shape, but we can still apply the same method to read the values we need.

Go to the value of 3 on the y-axis and then draw a horizonal line across to the graph. Note that there are two points where our line will cross the graph, so we will include both. Draw a vertical line down to the x-axis from these points. When y=3, x=2 and x=4

You May Also Like...

KS3 Maths Practice Papers

KS3 practice papers are perfect for preparing students for their KS3 maths tests and end of year exams. Order today and get the exam pack delivered to your door.

From: £4.99
View Product

KS3 Maths Worksheets

KS3 Maths Worksheets are an excellent way for KS3 students to prepare and practice for final term exams. They will ensure students have a sufficient base knowledge before going into KS4 and studying for their GCSEs.

£29.99
View Product

KS3 Maths Revision Cards

Whether you are buying these maths cards for a year 7 student who loves maths and wants to learn more or you are getting them for a reluctant year 9 student who has an end of year exam, these cards will be useful. Our KS3 maths revision cards are effective and will help to engage your child with their maths revision.

£8.99
View Product

GCSE Maths Revision Cards

Revise for your GCSE maths exam using the most comprehensive maths revision cards available. These GCSE Maths revision cards are relevant for all major exam boards including AQA, OCR, Edexcel and WJEC.

£8.99
View Product

GCSE Maths Revision Guide

The MME GCSE maths revision guide covers the entire GCSE maths course with easy to understand examples, explanations and plenty of exam style questions. We also provide a separate answer book to make checking your answers easier!

From: £14.99
View Product

GCSE Maths Predicted Papers 2022 (Advance Information)

GCSE Maths 2022 Predicted Papers are perfect for preparing for your 2022 Maths exams. These papers have been designed based on the new topic lists (Advance Information) released by exam boards in February 2022! They are only available on MME!

From: £5.99
View Product