# 9.09 Timelines

Lesson

## Ideas

Being able to locate numbers on a  number line  can help us in this lesson.

### Examples

#### Example 1

Plot 3 on the number line below.

Worked Solution
Create a strategy

Identify where the integer 3 is placed on the number line.

Apply the idea

On the number line, we can plot the point in the mark labeled with a 3.

Idea summary

We can plot an integer on the number line by drawing a point on the line above that integer.

## Timelines

Let's see how to make a timeline of our school day.

### Examples

#### Example 2

Which of the following timelines is correctly scaled?

A
B
C
Worked Solution
Create a strategy

Choose the timeline that counts up by the same amount of time every tick.

Apply the idea

Among the choices, Option A is a timeline that is correctly scaled as the distance between each time is only 1 hour and there are 4 spaces between each hour.

Idea summary

Timelines should be scaled so that each tick goes up by the same amount of time.

Each tick could go up by a certain number of years, months, weeks, days, hours, minutes or seconds.

## Interpret timelines

We can also read a timeline to learn about things happening at different times of the day.

### Examples

#### Example 3

Consider the following timeline.

a

What is the scale of the timeline?

A
20 years
B
30 years
C
10 years
Worked Solution
Create a strategy

Use the fact that the scale of a timeline is represented by the length of one interval on that timeline.

Apply the idea

To get the scale of the timeline, we determine the length of each two interval.

Since the distance between the years for two consecutive intervals is equal, then the scale of the timeline is 20 years. So, the correct answer is Option A.

b

Susana's birthday is in the year 1980, which point is it on the timeline?

A
A
B
B
C
C
Worked Solution
Create a strategy

Find the point that is plotted above the number 1980 on the timeline.

Apply the idea

From the timeline, it can be seen that point B is year 1980.

So, Option B is the correct answer.

Idea summary

When we make, or read, a timeline, we need to know if it's using 12 or 24 hour time, and digital or analogue.

### Outcomes

#### MA3-13MG

uses 24-hour time and am and pm notation in real-life situations, and constructs timelines