The length of CE is 10 cm
Since we know that ABCD and EFGH are congruent, Then the measure of their corresponding sides will be the same.
- AD = 17 , Then ED = 17
- AB = 7 ; Then CD = 7
To find CE ;
ED = CE + CD
17 = CE + 7
CE = 17 - 7
CE = 10 cm
Hence, length of CE is 10 cm