The problem asks for a proof showing that $EC = 4$ using the given figure. Let's analyze it step-by-step.

Analysis and Proof:

1. Understanding the Figure:
   The figure consists of two line segments:

   • Line Segment $AB$: $AB$ is a horizontal line segment with $A$ and $B$ as endpoints. The length of $AB$ is given as 2 units.
   • Line Segment $CE$: $CE$ is a vertical line segment with $C, D,$ and $E$ marked along it.

2. Key Observations:

   • It appears that $AB$ is marked as congruent to $CD$. This means $CD$ also has a length of 2 units.
   • Similarly, $DE$ is marked as congruent to $AB$ and $CD$, so $DE$ also has a length of 2 units.

3. Calculating $EC$:
   Since $CE$ is the sum of the lengths of $CD$ and $DE$, and both $CD$ and $DE$ have lengths of 2 units each: $EC = CD + DE = 2 + 2 = 4$

4. Conclusion:
   Therefore, the length of $EC$ is 4 units, which satisfies the given condition.

Would you like a more detailed explanation or have any questions?

Here are 5 related questions to explore further:

1. What does it mean for two line segments to be congruent?
2. How can we prove the congruence of two line segments geometrically?
3. What is the difference between vertical and horizontal congruence?
4. How would the problem change if $AB$ had a different length?
5. How do we define the sum of line segment lengths in geometry?

Tip: When working with geometric figures, always verify congruence and parallel relationships to simplify problem-solving.