Answer:
4 units
Explanation:
A transformation is the movement of a point from one position to another position. If a shape is transformed all its points are also transformed. Types of transformations are translation, rotation, reflection and dilation.
If a shape is transformed, the length of its sides and shape remains the same, only the position changes.
If Line segment AB has a length of 4 units. It is translated 1 unit to the right on a coordinate plane to obtain line segment A'B, the length of A'B' remains the same which is 4 unit. To prove this:
Let A be at (
) and B be at (
). The length of AB is:

If AB is translated to the right by 1 unit the new points are A' at (
) and B' at (
). The length of A'B' is:

AB = A'B' = 4 units