Answers:
- A) incorrect
- B) correct
- C) correct
- D) incorrect
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Explanation:
A)
The first letter of any ray <u>must</u> be the endpoint. So we must start with point Q and nothing else. The ray names for this could be "ray QR "or "ray QS". So there's no way we can start with point S as it's not an endpoint. The order matters when it comes to naming rays.
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B)
When naming a segment, we just list the two endpoints. The order doesn't matter (in contrast to a ray where it does matter). So "segment SQ" is one valid name for this. The other valid name is "segment QS".
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C)
Assuming all three points on the same plane, then we can name this plane SRQ. The order of the letters doesn't matter. You need 3 points to define a plane. The points must all be in the plane and the points cannot be on the same line (aka they can't be collinear).
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D)
We cannot name a line with simply one point. There isn't enough info to determine where the line is aimed with just one point. Imagine the line able to spin around point Q (like a propeller blade). As you can see, we cannot nail down the line. However, having two different points will be able to nail down the line.
In short: you need 2 points to define a line.
The same goes for a line segment and a ray.
