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 but different y-intercepts.

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 slopes m1 and m2, when are they parallel?

Back

Two lines are parallel if m1 = m2.

Front

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

Back

Two lines are perpendicular if m1 * m2 = -1.

Front

What is the slope of a line parallel to y = 3x + 2?

Back

The slope of a line parallel to y = 3x + 2 is 3.

Front

What is the slope of a line perpendicular to y = 4x - 1?

Back

The slope of a line perpendicular to y = 4x - 1 is -1/4.

Front

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

Back

The slope of a line parallel to y = -2x + 5 is -2.

Front

What is the slope of a line perpendicular to y = 1/3x + 4?

Back

The slope of a line perpendicular to y = 1/3x + 4 is -3.

Front

If a line has a slope of 2, what is the slope of a line parallel to it?

Back

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

Front

If a line has a slope of -1, what is the slope of a line perpendicular to it?

Back

The slope of a line perpendicular to it is 1.