Question

Describe the difference between parallel and perpendicular lines, their slopes and graphs

Answer 1

To provide a short definition,

Parallel lines are lines as the word suggests "parallel" which means they will stay side by side and never cross.

Perpendicular lines are lines that cross, usually to determine perpendicular lines you would take a slope and negatively reciprocate it.

Perpendicular:

1/2 -> -2

Parallel:

1x + 3

1x

Answer 2

Parallel lines have the same slopes (but different y intercepts). Parallel lines never cross. Parallel lines are the same distance from each other no matter where you are on either line. Think of it like a pair of perfectly straight railroad tracks.

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Perpendicular lines cross at one point. The two lines form a 90 degree angle. The two slopes multiply to -1, which is another way of saying that the slopes are negative reciprocals of one another. For example, a line with a slope of 2/3 and another line with a slope of -3/2 has these two values multiply to -1; therefore showing they are perpendicular lines.