First box is EF.
Second box is segment congruence postulate.
Third box is segment additon postulate.
Fourth box is DF. For this one the last sentence basically gives you the answer.
Just so you know for the fourth I guessed on if it's DF lined or DF unlined. I made my educated guess on the fact that the last line doesn't have a line. I hope this helps, and please tell me if I got something wrong, or my explanation wasn't sufficent enough for you.
Answer:
The first question would likely be y=10.
The second question would likely be x=20.
Point, line, plane, Ray, segment, circle for a few
Answer:
https://www.mathsisfun.com/adding-decimals.html
This has an explanation.
