Which undefined terms are needed to define parallel lines?
point, line
line, plane
coplanar, line
point, coplanar

answer;

-point and line

explanation;

the pair of undefined terms that is used to define the term parallel lines is a point and line.

-there are three words in geometry that are not formally defined (undefined) these words are point, line and a plane. from these three terms all other terms can be defined. a point has a location but no size, while a plane is a flat surface and no thickness, lines are set of points extending in either direction infinitely.

-points and lines are used to define parallel lines.

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