Final answer:
Parallel lines have the same slope and never intersect, while perpendicular lines intersect at a 90° angle and have slopes that are negative reciprocals of each other.
Step-by-step explanation:
To understand parallel and perpendicular lines, we need to consider their slopes when these lines are represented in a coordinate system. Parallel lines have the same slope and they never intersect with each other. This means that if you move along one of the parallel lines, you will always have the other line running exactly side by side at the same angle, no matter how far you go.
On the other hand, perpendicular lines intersect to form a 90° angle. The slopes of perpendicular lines are negative reciprocals of each other. For example, if one line has a slope of 2, a line perpendicular to it will have a slope of -1/2.
Therefore, the correct choice to describe parallel and perpendicular lines would be: A. Parallel lines have the same slope, while perpendicular lines have negative reciprocal slopes.