Equal Length Constraint
Makes the first selected line have the same length as the second line.
1. Start with two lines. Activate the Equal Length constraint and select the line whose length you want to change.
2. Select the line whose length you want to assign to the first line.
The first line's length changes to match the second. The equal constraint (an equal sign) appears.
3. If you edit either line, the equal length constraint will be maintained.