Question

which figures can be precisely defined by using only undefined terms? select three options.
□ angle
□ arc
□ circle
□ line segment
□ parallel lines

Explanation:

1. Circle: A circle is defined as the set of all points in a plane that are at a given distance (radius) from a given point (center). The terms "point" and "plane" are undefined terms in geometry, and "distance" can be related to the undefined term "line" (for measuring length). So a circle can be defined using undefined terms.
2. Line Segment: A line segment is defined as a part of a line that is bounded by two distinct endpoints. The term "line" and "point" (for endpoints) are undefined terms, so a line segment can be defined using them.
3. Parallel Lines: Parallel lines are defined as two lines in a plane that do not intersect; they are always the same distance apart. The terms "line" and "plane" (undefined terms) are used in this definition.

• An angle is defined as the figure formed by two rays sharing a common endpoint. The term "ray" is a defined term (based on "line" and "point"), so it's not just using undefined terms.
• An arc is a part of a circle, and since a circle is defined with undefined terms, but an arc also relies on the defined term "circle" (or needs more defined terms about the portion of the circle), so it's not purely defined by undefined terms.

Answer:

circle, line segment, parallel lines