IXL | Slopes of parallel and perpendicular lines | 8th grade math

or

Line
m
has
a
slope
of
7
6
.
Line
n
has
a
slope
of
^–7
6
. Are
line
m
and
line
n
parallel
or
perpendicular?

parallel

perpendicular

neither

ref_doc_title.

or

Learn with an example

question

Line
g
has
a
slope
of
^–5
6
.
Line
h
has
a
slope
of
5
6
. Are
line
g
and
line
h
parallel
or
perpendicular?

parallel

perpendicular

neither

key idea

Parallel lines have the same slope.

Perpendicular
lines
have
slopes
that
are
opposite
reciprocals,
like
a
b
and
^–b
a
.
The
slopes
also
have
a
product
of
^- 1.

solution

The
lines
are
not
parallel
because
^–5
6
and
5
6
are
not
equal.

The
lines
are
not
perpendicular
because
^–5
6
and
5
6
are
not
opposite
reciprocals:

^–5

6

Take the slope of line g

^–6

5

Find the reciprocal

6

5

Find the opposite

No,
^–5
6
and
5
6
are
not
opposite
reciprocals.

So, the lines are not perpendicular.

The lines are neither parallel nor perpendicular.

Looking for more? Try these:

Lesson: Equations of parallel and perpendicular lines

or

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Work it out

Not feeling ready yet? These can help:

AA.3Slope-intercept form: find the slope and y-intercept

Z.2Find the slope from two points

Y.3Parallel, perpendicular, and intersecting lines

Lesson: Equations of parallel and perpendicular lines