Parallel and Perpendicular Lines

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

If the slope of one line is m, what is the slope of a line that is perpendicular to it?

Back

The slope will be -1/m.

Front

If two lines have the same slope, what can we say about them?

Back

They are parallel lines.

Front

What is the slope of a line parallel to a line with slope 2?

Back

The slope is also 2.

Front

What is the slope of a line perpendicular to a line with slope -4?

Back

The slope is 1/4.

Front

How can you identify parallel lines in a graph?

Back

They will never meet and will have the same steepness.

Front

What does it mean for two lines to be opposite reciprocals?

Back

If one line has a slope of m, the other line has a slope of -1/m.

Front

If a line has a slope of 0, what type of line is it?

Back

It is a horizontal line.

Front

If a line has an undefined slope, what type of line is it?

Back

It is a vertical line.