Slopes of Parallel and Perpendicular Lines

Front

Back

The slope (m) represents the rate of change of y with respect to x.

Front

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

Back

Two lines are parallel if their slopes are equal, i.e., m1 = m2.

Front

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

Back

Two lines are perpendicular if the product of their slopes is -1, i.e., m1 * m2 = -1.

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Back

Front

Back

Front

What are opposite reciprocals?

Back

Opposite reciprocals are two numbers whose product is -1; for example, 2 and -1/2.

Front

Back

The slope is -2.

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Back

Front

If a line has a slope of 0, what does that indicate about the line?

Back

A slope of 0 indicates a horizontal line.

Front

If a line has an undefined slope, what does that indicate about the line?

Back

An undefined slope indicates a vertical line.