Theory:

A line segment is bounded by two fixed endpoints. A line segment can be constructed:
  • Using ruler alone.
  • Using a ruler and a compass.
 
Using a ruler alone:
  
Problem: Construct a line segment of length \(3.5\) \(cm\) using a ruler.
 
Step 1: A ruler is taken, and zero is marked at one end. Let this point be marked as \(A\).

Step 2: The other point is marked at the required length, that is, \(3.5\) \(cm\). Let this point be marked as \(B\).
 
Now, \(AB\) is the required line segment.
 
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