The answer is: No, because we also need to know the type of proportionality
In mathematics, we talk about proportionality when two variables are related and this relationship is that there is a constant ratio between them. There are two types of proportionality.
1. Direct Proportionality:
If there are two variables x and y, we can write the relationship between them as follows:

So, by substituting the point in this equation we have that the constant of proportionality is:

2. Inverse Proportionality:
In this case, the relationship is:

So, the constant of proportionality is:

As you can see, we have found two different values of the constant of proportionality. So, it is necessary to know the type of proportionality.
Answer:
3
Step-by-step explanation:
A ball is 10 meters. Since 100 centimeters are in a meter, each ball has 100*10 = 1000 centimeters.
The teacher needs 70 strings each 40 centimeters. The total amount they need is 70*40 = 2800 centimeters.
Since a ball has 1000 centimeters, 2800 centimeters will need 3 balls for a total of 3000 centimeters.
The answer is A trust me I did it before