Question

the undefined terms line and plane are needed to precisely define which mathematical term?
line segment
perpendicular lines
parallel lines
ray

Explanation:

A line - segment is part of a line. Perpendicular and parallel lines are defined in terms of lines in a plane. A ray is part of a line. But perpendicular lines are precisely defined using the concepts of lines and planes (two lines in a plane are perpendicular if they intersect at a right - angle).

Answer:

perpendicular lines