Parallel and Perpendicular

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). Their slopes are negative reciprocals of each other.

Front

If two lines have slopes m1 and m2, what condition indicates they are parallel?

Back

If m1 = m2, then the lines are parallel.

Front

If two lines have slopes m1 and m2, what condition indicates they are perpendicular?

Back

If m1 * m2 = -1, then the lines are perpendicular.

Front

What is the slope of a vertical line?

Back

The slope of a vertical line is undefined.

Front

What is the slope of a horizontal line?

Back

The slope of a horizontal line is 0.

Front

Are lines with slopes 1/5 and 1/5 parallel, perpendicular, or neither?

Back

They are parallel.

Front

Are lines with slopes 3/4 and 4/3 parallel, perpendicular, or neither?

Back

They are neither.

Front

True or False: Perpendicular lines have the same slope.

Back

False.

Front

What is the slope of a line that is perpendicular to a line with a slope of 2?

Back

The slope of the perpendicular line is -1/2.