X = 80 + 20 = 100 degrees
The answer would be 901 because they said what is the least number they would need to read and their goal is MORE than 900. The amount of books that they already had is useless information (Ignore). They love giving trick questions. :)
Answer:

Step-by-step explanation:
Let points D, E and F have coordinates
and 
1. Midpoint M of segment DF has coordinates

2. Midpoint N of segment EF has coordinates

3. By the triangle midline theorem, midline MN is parallel to the side DE of the triangle DEF, then points M and N are endpoints of the midsegment for DEF that is parallel to DE.