Reason: Because the total amount of money is equal to the price of a book, and the price of a book is certain and proportional.

2. Out of proportion.

Reason: Because a person's height and weight have nothing to do, it is not necessarily that a person becomes fat when he grows taller, so it is out of proportion.

3. proportional.

Reason: Because perimeter/side length = 4, and 4 is certain and proportional.

4. Out of proportion.

Reason: Because the total number of pages is equal to the number of pages in each exercise book, the number of pages in each exercise book is certain, so it is in direct proportion.

5. Out of proportion.

Reason: area of circle = radius * radius * π

But the radius itself is a variable and uncertain, so it is out of proportion.

6. disproportionate.

Reason: Because the distance traveled+the remaining distance = the total distance traveled (certain), a positive proportion means that the division of two numbers is equal to a certain number, so it is out of proportion.

Teach you a good way to distinguish positive proportions:

When judging whether two related quantities are directly proportional, we should pay attention to these two related quantities, one of which changes with the other, but the ratio of their corresponding two numbers is not necessarily, so it cannot be directly proportional.

For example, a person's age and weight are not proportional, and the side length and area of a square are not proportional.

Hope to adopt! Please respect the achievements of others' labor, and plagiarism is strictly prohibited.

I wish you progress in your study! You can ask if you don't understand. Answer your questions at any time.