To find the length of the segment $DE$, we can use the information given about the segments $CE$ and $CD$.

Given:

• $CE = 11$ (the entire length of the segment)
• $CD = 9$ (the length from point $C$ to point $D$)

To find $DE$ (the length from point $D$ to point $E$), we subtract $CD$ from $CE$:

$DE = CE - CD = 11 - 9 = 2$

Thus, the length of segment $DE$ is $2$ units.

Would you like more details or have any questions?

Here are some related questions you might find useful:

1. How do you find the length of a line segment using the distance formula?
2. What happens when the point $D$ is the midpoint of $CE$?
3. Can a segment have a negative length? Why or why not?
4. How would you find $CD$ if you were given $DE$ instead?
5. What are the properties of a line segment in geometry?

Tip: When working with line segments, always ensure the sum of the parts equals the whole. This can help verify your calculations.