A triangle for
which
all interior
angles are
acute.
The distance
from
the apex of
a cone to
the base.
Formally, the
shortest line
segment betw
een the apex
of a cone and
the (possibly
extended)
base. Altitude
also refers to
the length of
this segment
In plane
geometry or so
lid geometry,
the bottom of
a figure. If the
top is parallel
to the bottom
(as in a
trapezoid or
prism), both
the top and
bottom are
called bases.
Point B is
between
points A and C
if it is on
the line
segment conn
ecting A and
C.
A box shape
in three
dimensional
figure.
Formally,
a polyhedron f
or which
all faces are re
ctangles.
A three
dimensional fig
ure with a
single
base tapering
to an apex.
The base can
be any simple
closed curve.
Often the
word cone ref
ers to a right
circular cone.
A regular
polyhedron for
which
all faces are sq
uares.
Note: It is one
of the
five platonic
solids.
A threedimensional
geometric figure
with parallel
congruent base
s. The bases can
be shaped like
any closed
plane
figure (not
necessarily
a circle) and
must be
oriented
identically.
A geometric
figure made up
of two right
circular
cones placed a
pex to apex as
shown below.
Typically a
double cone is
considered to
extend infinitely
far in both
directions,
especially when
working
with conic
sections
and degenerat
e conic
sections.
A quadrilateral
with two pairs
of adjacent
sides that
are congruent.
Note that
the diagonals
of a kite are
perpendicular.
A polygon with
eight sides.
Two distinct co
planar lines th
at do not
intersect. Note:
Parallel lines
have the
same slope.
A polygon with
five sides.
A solid
with parallel
congruent ba
ses
which
are
both polygons.
The bases must
be oriented
identically.
The lateral
faces of a
prism are
all parallelogra
ms or rectan
gles.
A polyhedron
with
a polygonal b
ase and later
al faces that
taper to
an apex. A
pyramid with
a triangular
base is called
a tetrahedron.
A part of a
line starting at
a
particular poin
t and
extending infini
tely in one
direction.
A transformation
in which
a geometric
figure is
reflected across
a line, creating a
mirror image.
That line is called
the axis of
reflection.
Identical in
shape,
although not
necessarily the
same size.
A three
dimensional
solid consisting
of all
points
equidistant
from a
given point.
A rectangle
with all
four sides of
equal length.
Formally, a
square is a
quadrilateral
with
four
congruent
sides and
four
congruent
angles (all
90°).