Parallel and Perpendicular Lines

Front

What are parallel lines?

Back

Lines that never intersect and have the same slope.

Front

What are perpendicular lines?

Back

Lines that intersect at a right angle (90 degrees) and have slopes that are opposite reciprocals.

Front

If two lines have slopes m1 and m2, what condition must be met for them to be perpendicular?

Back

m1 * m2 = -1.

Front

What is the slope of a line represented by the equation y = mx + b?

Back

The slope is 'm'.

Front

How do you find the slope between two points (x1, y1) and (x2, y2)?

Back

Slope (m) = (y2 - y1) / (x2 - x1).

Front

What is the slope of the line through the points (2, 3) and (4, 7)?

Back

m = (7 - 3) / (4 - 2) = 2.

Front

What is the equation of a line that is perpendicular to y = 3x + 1?

Back

y = -1/3x + b (where b is any y-intercept).

Front

What is the midpoint formula for two points (x1, y1) and (x2, y2)?

Back

Midpoint = ((x1 + x2)/2, (y1 + y2)/2).

Front

Find the midpoint between A(1, 2) and B(3, 4).

Back

Midpoint = ((1 + 3)/2, (2 + 4)/2) = (2, 3).

Front

What is the slope of a horizontal line?

Back

The slope of a horizontal line is 0.