E’Bryant Lopez – 5th
Acute Triangle
A triangle for which
all angles are acute.
Cone
A three dimensional
figure with a
single base tapering
to an apex. The base
can be any simple
closed curve. Often
the word cone refers
to a right circular
cone.
Decagon
A polygon
with 10 sides.
Heptagon
A polygon with
seven sides. Some
authors also use the
name septagon instead
of heptagon.
Cube
A regular
polyhedron for
which
all faces are squares.
Hexagon
A polygon with
six sides.
Nonagon
A polygon with
nine sides.
Undecagon
A polygon with
eleven sides.
Octagon
A polygon with
eight sides.
Parallel Lines
Two distinct
coplanar lines
that do not
intersect. Note:
Parallel lines
have the
same slope.
Box
A box shape in 3D space.
Formally, a polyhedron for
which all faces
are rectangles.
Pentagon
A polygon with
five sides.
Polyhedron
A solid with no
curved surfaces o
r edges.
All faces are poly
gons and all
edges are line
segments.
Pyramid
A polyhedron with
a polygonal base an
d lateral faces that
taper to an apex. A
pyramid with
a triangular base is
called a tetrahedron.
Rhombus
A parallelogram
with four congruent
sides. Note that
the diagonals of a
rhombus
are perpendicular (a
s is the case with
all kites).
Sphere
A three
dimensional solid co
nsisting of all
points equidistant fr
om a given point.
This point is the
center of the sphere.
Square
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°).
Trapezoid
A quadrilateral whic
h has a pair of
opposite sides which
are parallel. The
parallel sides are
called the bases, and
the other two sides
are called the legs.
Rectangle
A box shape on
a plane. Formally, a
rectangle is
a quadrilateral with
four congruent
angles (all 90°)
Oval
An eggshaped curve. Note:
An oval is not the
same as an ellipse.