Which pair of undefined terms is used to define a ray?

A point and a line.

Further explanation:

Ray is part of the line with one endpoint. Ray is an endless straight path in one direction from a starting point, e.g., .

The arrow above the point shows the direction of the longitudinal beam. The length of the ray cannot be calculated.

Undefined terms are basic figure that is not defined in terms of other figures. The undefined terms (or primitive terms) in geometry are a point, line, and plane.

These key terms cannot be mathematically defined using other known words.

A point represents a location and has no dimension (size).  It is labeled with a capital letter and a dot.

A line is an infinite number of points extending in opposite directions that have only one dimension. It has one dimension. It is a straight path and no thickness.

A plane is a flat surface that contains many points and lines.  A plane extends infinitely in all four directions.  It is two-dimensional.  Three noncollinear points determine a plane, as there is exactly one plane that can go through these points.

the clues that signal the reader should change tone are the punctuation marks, the grammatical signs. for example, the quotation marks at the beginning of something someone else said literally or the exclamation marks.

the tone of the first line of dialogue until "gettysburg" is a kind tone, a tone of advise. the narrator is trying to the other person in doing something he or she obviously is finding hard to do by giving a piece of advise and bringing up a memory of a successful similar case.

the clue that the reader understand how to read the word "bang" is the exclamation mark. it gives the word a surprise tone, a strong accent.

the best tone for reading the word "bang" is an exciting tone, a surprise one, even a loud one.

the words that should be read with a formal tone are the ones that give factual information. the sentence: mister lincoln couldn't think of anything to say at the gettysburg" gives information about an event and it needs to be read formally, also, when the narrator wants to transmit calmness, a formal and slow tone is needed, because people also transmit messages with the vibrations of our voices and tones.

95.03 is the answer. hope this !