Answer:
18) A: only if you have an additional point not on the line.
19) D: No, because all the points may be on the same line.
Explanation:
There are basically 4 ways we can determine a plane and they are;
- When we have three non - collinear points: What this means is that if we have three points that are not on one line, then it means that only one particular plane can pass through those points.
- When we have a line and a point that's not on the line
- When we have two lines that intersect each other.
- When we have two lines that are parallel to each other.
From the four conditions above, we can now answer the question;
18) You can only have a plane if there is an additional point not on the line.
Option A
19) Having just three points may not always be sufficient to have a plane because it's possible that the three points may be on the same line which is not a condition for a plane. Thus, option D is correct.