Parallel and Perpendicular Lines

Front

What is the definition of parallel lines?

Back

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

Front

What is the definition of perpendicular lines?

Back

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

Front

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

Back

Two lines are parallel if m1 = m2.

Front

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

Back

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

Front

What is the slope of a line perpendicular to the line y = mx + b?

Back

The slope of a line perpendicular to y = mx + b is -1/m.

Front

Given the line y = 3x + 2, what is the slope of a line perpendicular to it?

Back

The slope of a line perpendicular to y = 3x + 2 is -1/3.

Front

What is the slope of the line y = -2/3x + 2?

Back

The slope of the line y = -2/3x + 2 is -2/3.

Front

What is the slope of the line y = 3/2x + 9?

Back

The slope of the line y = 3/2x + 9 is 3/2.

Front

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

Back

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

Front

How do you find the equation of a line given a point and a slope?

Back

Use the point-slope form: y - y1 = m(x - x1), where (x1, y1) is the point and m is the slope.