Question

Which ones are correct or incorrect? thanks! :)

Answer 1

Answers:

• A) incorrect
• B) correct
• C) correct
• D) incorrect

=====================================================

Explanation:

A)

The first letter of any ray must 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.

-------------------------

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".

-------------------------

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).

-------------------------

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.