Answer: The length of A'T' is 3 units.
Step-by-step explanation: Given that a translation takes triangle CAT to triangle C'A'T'.
We are to find the length of A'T'.
We know that
if a figure is translated, then its size and shape remains the same. Only the x and y co-ordinates are changed by the same units.
So, the lengths of the sides of the figure also remains the same.
Therefore, if triangle CAT is translated to C'A'T', then the length of A'T' is equal to the length of AT.
From the graph, we note that the length of side AT is 3 units.
So, the length of side A'T' is also 3 units.
Thus, the length of A'T' is 3 units.