Question

how do you know if two line segments are perpendicular? a. their slopes are reciprocals. b. their slopes are equal. c. the slope of one is the negative of the slope of the other d. their slopes are negative reciprocals.

Explanation:

Perpendicular lines (and their segments) have slopes that multiply to -1, meaning each slope is the negative reciprocal of the other. Option A describes reciprocal slopes (product = 1, not perpendicular). Option B describes parallel lines. Option C describes slopes that are negatives (product = -m², not -1 unless m=1). Only option D matches the definition.

Answer:

D. Their slopes are negative reciprocals.