Part a)
You can name planes by one letter or using three points belonging to it that are not on the same line.
Another name for plane X could be:
- Plane ABF, Plane BCF or Plane ACF. You may also get different names by reordering the three letters.
Part b)
Coplanar means 'on the same plane'.
The points on the same plane as point A are:
Part c)
Collinear means 'on the same line'.
Other points on the same line as point C are:
Part d)
The line that intersects ED is:
- AC, it can be also named AB or BC.