parallel and perpendicular lines

8
Parallel & Perpendicular Lines A Brief Overview

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Identifying parallel and perpendicular lines from a graph using slope

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Page 1: Parallel and Perpendicular lines

Parallel & Perpendicular Lines

A Brief Overview

Page 2: Parallel and Perpendicular lines

Parallel Lineshave the SAME

SLOPE & DIFFERENT

Y-INTERCEPTS

Page 3: Parallel and Perpendicular lines

In this example, both lines A & B have slopes equal to 1/2The lines cross the y-axis in different placesThe lines are PARALLEL

Page 4: Parallel and Perpendicular lines

In this example, the lines appear to be parallel, but actually have different slopes. The lines are NOT PARALLEL

Page 5: Parallel and Perpendicular lines

PERPENDICULAR LINES

have OPPOSITE RECIPROCAL slopesThis means that the sign of the slopes are reversed and

the slopes, when written as a fraction, are flipped

**if you multiply the slopes of perpendicular lines, the answer will be -1 with the exception of a vertical line and

a horizontal line

Page 6: Parallel and Perpendicular lines

Examples of opposite reciprocal slopes:

-3 44 3

& 0 & Undefined 1 -22

&

Page 7: Parallel and Perpendicular lines

Line A has a slope of 2/3

Line B has a slope of -3/2

2/3 & -3/2 are opposite reciprocals, the lines are perpendicular

Page 8: Parallel and Perpendicular lines

Line A has a slope of 4/3

Line B has a slope of -3/5

4/3 & -3/5 are NOT opposite reciprocals, the lines are NOT PERPENDICULAR