IXL | Parts of three-dimensional figures | 8th grade math

or

In the triangular prism shown below, which lines are parallel?

J

K

L

M

N

O

JL

and

KN

KN

and

MO

KL

and

KN

JM

and

KN

ref_doc_title.

or

Learn with an example

question

In the cube shown below, which lines are parallel?

O

P

Q

R

S

T

U

V

OR

and

OS

OR

and

SV

SV

and

OP

OR

and

RV

key idea

Parallel lines are lines that are in the same plane and never intersect.

solution

Find
OR
and
OS
.

O

P

Q

R

S

T

U

V

OR
and
OS
are
intersecting
lines
because
they
meet
at
point
O.
They
are
not
parallel
lines,
because
parallel
lines
must
never
intersect.

Find
OR
and
SV
.

O

P

Q

R

S

T

U

V

OR
and
SV
are
parallel
lines
because
they
are
in
the
same
plane
( ORS )
and
never
intersect.

Find
SV
and
OP
.

O

P

Q

R

S

T

U

V

SV
and
OP
are
skew
lines
because
they
are
not
in
the
same
plane.
They
are
not
parallel
lines,
because
parallel
lines
must
be
in
the
same
plane.

Find
OR
and
RV
.

O

P

Q

R

S

T

U

V

OR
and
RV
are
intersecting
lines
because
they
meet
at
point
R.
They
are
not
parallel
lines,
because
parallel
lines
must
never
intersect.

So,
the
parallel
lines
are
OR
and
SV
.

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Teacher tools

Work it out

Not feeling ready yet? These can help:

AA.1Bases of three-dimensional figures

Y.3Parallel, perpendicular, and intersecting lines

DD.1Lines, line segments, and rays