Question

What is CD equal to ?

Answer 1

Judging by the model I would assume that ΔDBC is congruent to ΔDBA.

Thus, line CD should be congruent to line AD as well, which the solution should be line CD=13 units.

Answer 2

Because of CPCTC (Congruent Parts of a Congruent Triangle are Congruent)

This means that because of CPCTC, line AD is congruent with CD

AD ≅ CD

AD = 13, ∴ CD = 13

13 is your answer


hope this helps