Indirect Measurement

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GLE 0706.2.3

SPI: 0706.2.7

Indirect Measurement is a way to find the measurement of things around you. For instance, have you ever wondered if the Statue of Liberty has a nose that is too big?

Typically, your nose is 1/8 the distance of your arm.Try to use that ratio to find the answer about Lady Liberty’s nose.

You will need a ruler or tape measure for this.

First measure your arm and your nose….

Take a look at the next slide.

Write your answers as a ratio:

Length of your noseLength of your arm

Come closer and look at the length of Lady Liberty’s arm.

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Now take the ratio from your measurements and write the proportion

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Length of your nose

Length of your arm

Length of Lady Liberty’s nose

=x

Length of your nose

Length of your arm

Length of Lady Liberty’s nose

=x

Try measuring your arm raised as if you are holding a torch.

Now let’s use the ratio that your nose is usually 1/8 of your arm……

1

Length of Lady Liberty’s nose=

x8

x

Click once to see the actual size revealed.

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Now let’s try to find the height of the Eiffel Tower.

What I know is that on a sunny day, its shadow is 328 feet long.

I know that it takes a fourteen quarters stacked on top of each other to make an inch. What is your value in quarters? Would you be worth more if they were stacked or laid end to end?

If you have ever seen Jurassic Park, you saw how big the dinosaurs were compared to the people. Pretend that they made a large Human to watch over the animals. What would be the scale factor if a 64 inch person was made to be 160 feet?

The scale factor tells you how many times bigger than “normal” that person really is.You must make all units of measure the same….

64 inches

160 feet64 inches

160 x 12

64 inches1920 inches

= =

Now take the:

64 inches

1920 inches And simplify

1/30 inches

This means that the person was created 30 times his normal size.

A real car is 6 inches long, while the real car is 9 feet long. What is the scale of the model?

Remember to put Model on top of the actual measurement, make them the same unit and reduce !

6 inches 9 feet

6 inches 108 inches

118

The diameter of a tire on the model of a car is 0.4 inches. What is the diameter of a tire on the actual car?

A model car has a scale factor of 1/64…

HintThe scale means that the car is really 64 times larger.

So, .4 x 64 = 25.6