Name
Acute Angle
Definition
An angle that is
between 0˚and
90˚
Right Angle
An angle that is
exactly 90˚
Obtuse Angle
An angle that is
between 90˚
and 180˚
Straight Angle
An angle whose
measure is 0˚ or
180˚
Two lines
intersect and
opposite angles
are the same.
Two angles that
add up to be
90˚
Vertical Angle
Complementary
Angles
Supplementary
Angles
Two angles that
add up to 180˚
Adjacent Angles
Angles that are
side by side
Transversal
A line that
intersects
through parallel
lines
Symbol
Picture
Interior Angles
Angles between
the parallel
lines when
there is a
transversal
Exterior Angles
Angles on the
outside of the
parallel lines
when there is a
transversal
Angles in the
same relative
position or spot
Corresponding
Angles
Alternate Interior
Angles
Alternate
Exterior Angles
Point
Line
Line Segment
Interior angles
on the opposite
side of the
transversal that
are the
congruent
Exterior angles
on the opposite
side of the
transversal that
are congruent
An exact
location in
space
A flat, straight
path that
extends forever
in both
directions
Part of a line
with endpoints
Point A
.
A
AB
AB
Ray
Vertex
Vertices (pl.)
Intersecting Lines
A straight path
that starts at
and endpoint
and extends
forever in one
direction
The point
where two or
more rays meet
and form an
angle
Lines that cross
and meet at a
point
Perpendicular
Lines
Lines that
intersect and
form a right
angle
Parallel Lines
Two straight
lines that are
always the
same distance
apart
Plane
A flat surface
that extends
forever in all
directions
Polygons
Is a closed plane
figure with
straight sides
that are line
segments
Triangle
3 sides, angles,
and vertices
Quadrilateral
4 sides, Angles,
Vertices
CP
Plane BGR
Pentagon
5 sides, angles,
and vertices
Hexagon
6 sides, angles,
and vertices
Heptagon
7 sides, angles,
and vertices
Octagon
8 sides, angles,
and vertices
Nonagon
9 sides, angles,
and vertices
Decagon
10 sides, angles,
and vertices
11 sides, angles,
and vertices
12 sides, angles,
and vertices
A triangle with
all 3 angles and
sides congruent
Hendecagon
Dodecagon
Equilateral
Triangle
Isosceles Triangle
A triangle with
2 Congruent
Angles and
Sides
Scalene
Triangle
A triangle that
has no sides or
angles the same
Acute Triangle
A triangle
whose angles
are all Acute
Obtuse Triangle
A triangle that
has only one
Obtuse angle
Right Triangle
A triangle with
one Right angle
Parallelogram
Opposite sides
are parallel and
congruent
Quadrilateral
Rectangle
Opposite sides
are parallel and
congruent
(parallelogram)
with four right
angles
Opposite sides
are parallel and
congruent
(parallelogram)
All sides are
congruent
Is a
Parallelogram,
and a
Quadrilateral
Rhombus
Is a
Parallelogram
and a
Quadrilateral
Square
Opposite sides
are parallel and
congruent.
Four Right
Angles and
Congruent sides
Trapezoid
Quadrilateral
with exactly
two parallel
sides
Quarilateral
Parallelogram
Rectangle
Rhombus