Parallel and Perpendicular Lines

Front

What are parallel lines?

Back

Parallel lines are lines in a plane that never meet or intersect, no matter how far they are extended. They have the same slope.

Front

What are perpendicular lines?

Back

Perpendicular lines are lines that intersect at a right angle (90 degrees). The slopes of perpendicular lines are negative reciprocals of each other.

Front

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

Back

If two lines have the same slope, they are parallel.

Front

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

Back

The slope of a line perpendicular to a line with a slope of 4 is -1/4.

Front

How do you determine if two lines are parallel or perpendicular from their equations?

Back

Convert the equations to slope-intercept form (y = mx + b) and compare the slopes. If slopes are equal, lines are parallel; if slopes are negative reciprocals, lines are perpendicular.

Front

What is the slope of the line represented by the equation y = 2x + 3?

Back

The slope of the line is 2.

Front

If the equation of a line is y = -3x + 1, what is the slope of a line that is perpendicular to it?

Back

The slope of a line that is perpendicular to y = -3x + 1 is 1/3.

Front

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

Back

Two lines are neither parallel nor perpendicular if they intersect at an angle that is not 90 degrees and do not have the same slope.

Front

What is the relationship between the slopes of two parallel lines?

Back

The slopes of two parallel lines are equal.

Front

If one line has a slope of 1/2, what is the slope of a line that is parallel to it?

Back

The slope of a line that is parallel to it is also 1/2.