Straight line graphs

Straight line graphs for GCSE Geography Edexcel Higher: what it means, how to set the working out, and the questions it is asked in.
  • GCSE
  • Edexcel
  • Geography
  • Higher
  • Spec N4 · N12 · N17
  • 4 min read
  • 8 revision boxes

Introduction

2 boxes
1 min read

What is straight line graphs?

Listen to this box

Transcript

A short spoken summary of straight line graphs and where it is used.

A spoken walk-through of straight line graphs before you read the notes.
Work through the method one line at a time and write down what changes at each step.
Worth knowing: ×10\times 10 moves every digit one column left.
6 rows

The straight line graphs reference table

Check the answer against an estimate before you move on, so a place-value slip is caught here.
The layout below is the one the mark scheme expects.

Diagram showing straight line graphs laid out step by step

The same idea drawn out, so the method is visible.
Term
Meaning
Example
Row 1 column 1
Row 1 column 2
a2+b2=c2a^2 + b^2 = c^2
Row 2 column 1
Row 2 column 2
×10\times 10 moves every digit one column left

Learning

4 boxes
5 steps

How to work with straight line graphs

Read the units in the question before you start; a converted unit is the most common slip.
  1. Read the question and write down what is being asked for.
  2. Set out the working for straight line graphs in the order the method gives.
  3. Substitute the values and simplify.
  4. Check the answer against an estimate before writing it down.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: a2+b2=c2a^2 + b^2 = c^2.
Answer: a2+b2=c2a^2 + b^2 = c^2
3 rules

Key facts: Straight line graphs

The specification wording is precise here, and the mark scheme follows that wording exactly.
  • Rule 1

    How straight line graphs behaves in the 1st of the cases the specification names.
    160\approx 160
  • Rule 2

    How straight line graphs behaves in the 2nd of the cases the specification names.
    49=7\sqrt{49} = 7
  • Rule 3

    How straight line graphs behaves in the 3rd of the cases the specification names.
    160\approx 160
5 steps

How to work with straight line graphs

Work through the method one line at a time and write down what changes at each step.
  1. Read the question and write down what is being asked for.
  2. Set out the working for straight line graphs in the order the method gives.
  3. Substitute the values and simplify.
  4. Check the answer against an estimate before writing it down.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: a2+b2=c2a^2 + b^2 = c^2.
Answer: ×10\times 10 moves every digit one column left
2 rules

Key facts: Straight line graphs

Check the answer against an estimate before you move on, so a place-value slip is caught here.
The layout below is the one the mark scheme expects.

Diagram showing straight line graphs laid out step by step

The same idea drawn out, so the method is visible.
  • Rule 1

    How straight line graphs behaves in the 1st of the cases the specification names.
    160\approx 160
  • Rule 2

    How straight line graphs behaves in the 2nd of the cases the specification names.
    160\approx 160
  • Rule 3

    How straight line graphs behaves in the 3rd of the cases the specification names.
    34×25\frac{3}{4} \times \frac{2}{5}

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Examples

2 boxes
4 marks · worked

Worked example: straight line graphs

Sketch the shape even when the question does not ask for one — it makes the next step obvious.
3 marks · worked

Practice question 8: a2+b2=c2a^2 + b^2 = c^2

The examiner marks the working, so a correct answer with no method still drops marks.
The layout below is the one the mark scheme expects.

Diagram showing straight line graphs laid out step by step

The same idea drawn out, so the method is visible.

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Common questions

How many marks is straight line graphs usually worth?
Between one and four, depending on how many steps the question asks for.
Is this on the GCSE Geography Edexcel Higher paper?
Yes — it sits in the Energy and matter strand.