Asteel beam can cut two different lengths for a project. assuming the weight of a steel beam is proportional to its length, what information would you need to know to write an equation that represents this relationship?

The information we will need to know is the value of k which is constant of proportionality.  

We are told that the weight of the beam is proportional to its' length.

This means if we denote the weight as W and the length as L, then, we can write the proportion as;

W ∝ L

Getting rid of the proportion symbol, we have;

W = kL

Where; K is a constant of proportionality.

What this means is that for us to write an equation that represents the relationship between the beams weight and length, we will need to  know the value of k which is constant of proportionality.

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None.

Step-by-step explanation:

You can write a statement of proportionality without any additional information:

... weight = k × length . . . . . . . . for some constant k

If you need to know the specific weight of a specific length, then you need to know the constant of proportionality (the value of k).

1 kilometer = 100,000 centimeters so, 27 kilometer= 2,700,000 centimeters