the question is in the attached below. thank you for your help , Please do not answer if you are not sure or simply doing it just to get points because i will report you and your answer. Thank you

First answer is DE≅ EF
Second answer is DE=EF by the ''segment congruence postulate''
Third answer is DE * EF + DF by the ''segment addition postulate''
The fourth answer is DE + DE = DF
Good luck!!!