# Functional Skills: Length

## Functional Skills: Length Revision

**Length**

Measuring **length **requires you to use **units**, this is key when measuring something. For instance, if you told someone the **length **of a block of wood was \textcolor{red}{14}, this wouldn’t mean anything. You would need to specify the **unit**, for example ‘the length of this block of wood is \textcolor{red}{14} cm’.

## Units of Length

The **length **of something is how long it is, from one end to the other.

The **common units** for length are **millimetres (mm)**, **centimetres (cm)**, **metres (m)** and **kilometres (km)**.

The conversions between these **units **are shown on the right:

**Switching** between these units is fairly straightforward and just requires you to **multiply** and **divide** by 10, 100 and 1000.

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**Comparing Lengths**

It is likely you will be required to compare **lengths** in real life context.

For example, you may be asked to compare the heights of several people or the widths/lengths of material or objects.

**Example: **A group of children are going to a theme park.

The minimum height for the ride called ‘Thrill Edge’ is 1.30 m.

Which children **cannot** ride on ‘Thrill Edge’?

We need to look for children who are less than 1.30 m.

**Luna**is only \boldsymbol{1.25}**m**, so she is too small to go on the ride.**Leo**is only \boldsymbol{1.29}**m**, so he is also too small to go on the ride.

The rest of the children are 1.30 m or taller, so they can all ride.

**Note:**

**Length** is sometimes also measured in **miles**, **yards** (yd), **feet** (ft) or **inches** (in).

Examples of these units being used are:

- Feet and inches being used to measure someone’s
**height**, e.g. someone’s height might be 5 feet 8 inches. **Distances**on road signs in the UK are measured in miles.

**Example 1: ****Converting Units of Length**

**a)** How many centimetres are there in 0.85 km?

**[1 mark]**

There are 100 **centimetres **in a **metre **and 1000 **metres **in a **kilometre**. Therefore to calculate the amount of **centimetres **in 0.85 **kilometres**, we need to do:

0.85\times100\times1000=85000 cm

**b)** Convert 41000 **millimetres **into **metres**.

**[1 mark]**

There are 10 **millimetres **in a **centimetre **and 100 **centimetres **in a **metre**. Therefore to convert 41000 **millimetres** into **metres**, we need to do:

41000\div10\div100=41 m

## Example 2: **Length Calculations**

Aiden is building a small brick wall that he wants to be 1.2 metres **high**.

Each brick is \boldsymbol{6} cm in height, how many bricks high will the wall be?

**[2 marks]**

We first need to **convert **the height of the brick wall into centimetres:

1.2 m =120 cm

Then **divide **the height of the wall by 6:

120\div6=20

So the wall would be \boldsymbol{20} bricks high.

**Example 3: Length Calculations**

Questions will sometimes ask you to do **calculations with length**.

Harper is swimming in a pool that is 25 m in length.

She swims to one end of the pool and back again.

How far in **total **does she swim?

**[1 mark]**

One length of the pool is 25 m, so 2 lengths will be:

25\times2=\boldsymbol{50} m

## Functional Skills: Length Example Questions

**Question 1:Â **Convert the following measurements:

**a)** 3.2 m into cm

**b)** 51 mm into m

**c)** 1091 cm into mm

**[3 marks]Â **

a) 3.2\times100=320 cm

b) 51\div10\div100=0.051 m

c) 1091\times10=10910 mm

**Question 2: **Convert the following measurements:

**a)** 43500 mm into m

**b)** 0.009 km into mm

**c)** 3126 cm into km

**[3 marks]**

a) 43500\div10\div100=43.5 m

b) 0.009\times10\times100\times1000=9000 mm

c) 3126\div100\div1000=0.03126 km

**Question 3: **Harold’s journey to school requires him to walk 350 m to the bus stop, then get on a bus and then walk another 900 m to his school once he gets off the bus.

The total distance he travels is 7.2 km.

Calculate how many kilometres Harold travels on the bus.

**[2 marks]**

Firstly, change 350 m and 900 m into km:

350 m =0.35 km

900 m =0.9 km

So, Harold travels 7.2-0.35-0.9=5.95 km on the bus.

**Question 4:Â **Mila is looking at buying a new rug for her living room. The maximum length the rug can be is 3.5 m.

Which rugs would fit in her living room?

**[2 marks]**

Only rugs 3.5 m or less will fit in her living room.

Rug B is 3.3 m in length so would fit.

Rug D is 3.1 m in length so would also fit.

So only rugs B and D will fit in her living room.

**Question 5: **Aria is completing a mini triathlon. She runs 5 km, swims 500 m and cycles 10 km. How far in total is the triathlon?

**[2 marks]**

Firstly, convert 500 m into km:

500 m =0.5 km

Then add up all the distance:

5+0.5+10=15.5 km