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.

Tags

CCSS.HSG.CO.A.1

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.

Tags

CCSS.4.G.A.1

CCSS.HSG.CO.A.1

Front

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

Back

Two lines are parallel if they have the same slope. For example, in the equations y = mx + b, if both lines have the same value of m, they are parallel.

Front

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

Back

Two lines are perpendicular if the product of their slopes is -1. If one line has a slope m1, the other line must have a slope m2 such that m1 * m2 = -1.

Front

What is the slope of a line perpendicular to y = 2x - 7?

Back

The slope of a line perpendicular to y = 2x - 7 is -1/2.

Tags

CCSS.8.EE.B.6

Front

What is the slope of a line parallel to y = 5/7x + 2?

Back

The slope of a line parallel to y = 5/7x + 2 is 5/7.

Tags

CCSS.8.EE.B.5

Front

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

Back

If two lines have the same slope, we can conclude that they are parallel.

Tags

CCSS.4.G.A.1

CCSS.HSG.CO.A.1

Front

If two lines have slopes of 3 and -1/3, what can we conclude about them?

Back

If one line has a slope of 3 and the other has a slope of -1/3, we can conclude that the lines are perpendicular.

Front

What is the slope of a line perpendicular to a horizontal line?

Back

The slope of a line perpendicular to a horizontal line is undefined, as it would be a vertical line.

Tags

CCSS.8.EE.B.5

Front

What is the slope of a line perpendicular to a vertical line?

Back

The slope of a line perpendicular to a vertical line is 0, as it would be a horizontal line.

Tags

CCSS.8.EE.B.5