Exercise 8

Estimating

(You'll be pleased to know that this is the last exercise. Will you qualify to become an inspector?)

When you are an inspector, there will be many occasions when you will need to measure things. In this exercise we will find out if you are any good at using the quick method of estimating lengths and heights.
Look at the building in the picture. Measuring the height would not be easy without a ladder and a long tape measure. Even then, it wouldn't be easy for one person, especially if the wind kept blowing your tape away.
The walls of the building are made of boards. If you measure the height of one board and multiply it by the number of boards, you will know how high the building is. Well, almost. There is a canopy at the front which makes the building a bit taller, but we won't bother about that.

The back wall of the building has 12 boards. Each board is 16cm high.

Question 1: How high is the back of the building?

Answer:   cm     

 

You can use the same method to estimate the height of the side panel of this truck. There are actually 14 boards but let's pretend there are 12.

There are 12 boards. Each board is 17cm high.

Question 2: How high is the side panel of the truck?

Answer:   cm     

Measuring a fence is slightly different because there are spaces between the strips of wood.

A fence has 40 strips of wood. Each strip is 8cm wide. Each space is 8cm. This means that you have 40 strips and 40 spaces.

Question 3: How long is the fence?

Answer:   cm     

This picture shows the edge of the platform. It is made of bricks. Can you think why it is painted white?
Inspectors need to know the length of platforms. Can you remember why? In the last exercise you had to work out the maximum length of a train.
You could measure a platform by pacing it, but let's imagine that you have a bad leg.

Each brick is 10cm wide. There are 1000 bricks along the edge of the platform.

Question 4: How long is the platform in metres?

Answer:   m     


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