parallel and perpendicular lines
DESCRIPTION
Identifying parallel and perpendicular lines from a graph using slopeTRANSCRIPT
Parallel & Perpendicular Lines
A Brief Overview
Parallel Lineshave the SAME
SLOPE & DIFFERENT
Y-INTERCEPTS
In this example, both lines A & B have slopes equal to 1/2The lines cross the y-axis in different placesThe lines are PARALLEL
In this example, the lines appear to be parallel, but actually have different slopes. The lines are NOT PARALLEL
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
Examples of opposite reciprocal slopes:
-3 44 3
& 0 & Undefined 1 -22
&
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
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