Parallel and Perpendicular Lines

Front

What are parallel lines?

Back

Parallel lines are lines in a plane that never meet. They have the same slope.

Front

What are perpendicular lines?

Back

Perpendicular lines are lines that intersect at a right angle (90 degrees). The product of their slopes is -1.

Front

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

Back

They are parallel.

Front

If the slopes of two lines are negative reciprocals of each other, what can we say about them?

Back

They are perpendicular.

Front

What is the slope of a line parallel to y = 3x + 5?

Back

The slope is 3.

Front

What is the slope of a line perpendicular to y = -2x + 1?

Back

The slope is 1/2.

Front

Are the lines represented by y = 4x + 1 and y = 4x - 3 parallel, perpendicular, or neither?

Back

They are parallel.

Front

Are the lines represented by y = 2x + 1 and y = -1/2x + 3 parallel, perpendicular, or neither?

Back

They are perpendicular.

Front

What is the slope of the line y = -5x + 2?

Back

The slope is -5.

Front

If two lines are neither parallel nor perpendicular, what can we say about their slopes?

Back

Their slopes are different and not negative reciprocals.