Line graphs

Line Graphs

These are graphs showing information that is connected in some way. For example, change over time.

Representing data using line graphs

Example 1

The table shows the number of correct answers over five days.

Day	Correct answers
Day 1	3
Day 2	5
Day 3	10
Day 4	13
Day 5	15

You are learning facts about mathematics and each day you do a test to see how good you are.

Solution

We need to have a scale that helps us to know how many centimeters will represent how many facts that you were correct.

Vertical scale: 1 cm represents 2 facts that you were right

Horizontal scale: 2 cm represents 1 day.

Interpretation of line graphs

The graph below shows the temperature over the year:

From the graph we can get the following data:

1. The month that had the highest temperature was August.
2. The month with the lowest temperature was February.
3. The difference in temperature between February and May is $32^\circ - 29^\circ = 3^\circ$
4. The total number of months that had temperature more than $30^\circ C$ was 9.