Parallel and Perpendicular

Front

What are parallel lines?

Back

Lines in a plane that never meet 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 negative reciprocals of each other.

Front

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

Back

m1 = m2.

Front

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

Back

m1 * m2 = -1.

Front

What is the slope of a line that is perpendicular to a line with slope 4?

Back

Front

What is the slope of a line that is parallel to a line with slope -3?

Back

-3.

Front

What is the negative reciprocal of 1/2?

Back

Front

What is the negative reciprocal of -3?

Back

Front

Which figure shows a set of parallel lines?

Back

Look for lines that do not intersect and have the same slope.

Front

Which figure shows a set of perpendicular lines?

Back

Look for lines that intersect at a right angle.