•E 8
D
1. Give two other names for AB.
2. Name three points that are collinear.
3. Give another name for plane F.
4. Name a point that is not coplanar with A, B, and C.
5. Give another name for CD.
6. Name three rays with endpoint B.
7. Name a pair of opposite rays.
8. Give another name for CD.

Problem 1

Two other names for line AB are

The order of the letters doesn't matter which is why AB is the same as BA. Line h is another name since the h is attached to the line.

Problem 2

Three points that are collinear are: C, B, and D

Those three points all fall along the same vertical line (line g)

Problem 3

Pick any three points you want in plane F as long as those points do not fall on the same line. The only three points we can pick are A, B and E. Those points are not all on the same line. They uniquely define plane F. So we can say "plane ABE" in place of "plane F". In this case, the order of the lettering does not matter.

Problem 4

Point E is not coplanar with A, B and C. Plane ABC is a vertical wall (of sorts) while point E is on the floor (plane F) away from the wall ABC. In contrast, a point like D is on plane ABC because line g goes through this plane as well.

Problem 5

Line CD can be written as

any of those are valid. All we need are two points that are on line CD. The order doesn't matter.

Problem 6

Start with point B. Then add on a letter that forms a ray or half a line. We could write

We cannot write ray BE since there is no line connecting the two points. Also, when it comes to naming rays, the order does matter. The first point is where we start and the second point is where the ray aims and goes on forever toward. Something like ray BC is not the same as ray CB (since the endpoint here is C instead of B).

Problem 7

One pair of opposite rays is BC and BD. They point in completely different directions and both fall on along the same straight line extended out infinitely in both directions. Put another way: gluing together the endpoints of opposite rays forms a line.

Problem 8

This seems to be a repeat of problem 5. I'm not sure if this is a typo or not.

b. heterotroph

explanation: