2. It is the measured length of the picture drawn on the book.

That is, it refers not to books, but to the length measured on actual objects (objects)

3. 1.6km (600000[cm] is also acceptable)

| - |

4. 1:5000000

Right or wrong

1. Yes, they are all 1: 100, etc. These are the reduction ratios, and 20: 1 is the enlargement ratio.

2. Wrong, it should be simplified to = 20km = 2 million cm.

Multiple choice

1.b, examples can be cited. It is easy to know that the higher the height, the smaller the bottom, so it is inversely proportional.

2.c, from the last question, we know that this is an enlarged scale, so one fiftieth is wrong, only 50 is optional, and 5 1 is ignored directly.

application problem

1. Distance from map: actual distance

You can get 10* 10/5=20.

So the ratio is 1:20.

Reason: Just add the distance data on the map to the actual distance ... Note that 10 should be simplified to100 mm. ..

2. let the actual distance = x.

From the distance on the map to the actual distance, a proportional formula can be listed (/divided).

1/5000000=3.4/x

Cross multiplication x = 3.4 * 5000000 =17000000 cm =170000 m =170000 km.

The reason is the same as the first question.

3. Total coal quantity = 12.5*32=400 tons.

400 days after storage (12.5-2.5) = 40 days.

Reason: Calculate the total coal quantity first, and then calculate the daily consumption after saving, so that the total coal quantity can be used after saving = days after saving.

4. Similarly, the ratio of the distance on the map to the actual distance can be obtained.

=4.2/ 1050* 1000* 10=4.2/ 1050000000

= 1/25000000( 1: 25 million)

Reason: Like the previous question, a set of formulas is enough, but it should be noted that when the units are not unified, the units must be unified first ~

I hope I can help you ~

Because time is pressing, I will answer directly first. If you don't understand anything, you can ask Baidu HI ~