Parallel & Perpendicular Slope

Front

What are parallel lines?

Back

Lines that never intersect and have the same slope.

Front

What are perpendicular lines?

Back

Lines that intersect at a right angle (90 degrees) and have slopes that are opposite reciprocals.

Front

What is the slope of a line?

Back

The ratio of the rise (vertical change) to the run (horizontal change) between two points on the line.

Front

If two lines have slopes m1 and m2, when are they parallel?

Back

When m1 = m2.

Front

If two lines have slopes m1 and m2, when are they perpendicular?

Back

When m1 * m2 = -1.

Front

What is the slope of a horizontal line?

Back

0.

Front

What is the slope of a vertical line?

Back

Undefined.

Front

How do you find the slope between two points (x1, y1) and (x2, y2)?

Back

Slope (m) = (y2 - y1) / (x2 - x1).

Front

If a line has a slope of 3, what is the slope of a line perpendicular to it?

Back

-1/3.

Front

What does it mean for two lines to be neither parallel nor perpendicular?

Back

They intersect at an angle that is not 90 degrees and do not have the same slope.