Polygons
Circles
Terms
Angles
Acute Triangle: A
triangle with three acute
angles.
Arc: any unbroken part
of the circumference of
a circle or other curved
line.
Census: An official count
of population and the
recording of other
demographic data such as
age, gender, income, and
education
Acute angle: An angle
that measures 1 degree to
89 degrees—a cute little
angle.
Equilateral: A triangle
with three congruent
sides and three
congruent angles.
Diameter: A line
segment that passes
through the center of a
circle or sphere and on
endpoints on the circle.
The diameter is equal to
the sum two radii.
Congruent: Having the
same size and same shape.
Adjacent angles: Two
angles with a common
side and vertex that do not
otherwise overlap.
Irregular: A polygon
that has sides that
measure differently and
angles that measure
differently.
Perimeter: The distance
around the outside of a
figure.
Isosceles: A triangle
with two congruent
sides and two congruent
angles.
Regular Tessellation: A
tessellation of one regular
polygon.
Obtuse angle: An angle
that measures 91 degrees
to 180 degrees—a fat
angle.
Obtuse Triangle: A
triangle with one obtuse
angle.
Radius: A line segment
from the center of a
circle or sphere to any
point on the circle or
sphere. The length of a
radius is half the length
of a diameter.
Tessellate: To make a
tessellation; to tile a
surface.
Quadrangle: A polygon
that has four angles—a
quadrilateral.
Pentagon: A five-
sided polygon.
Tessellation: A pattern of
shapes that covers a
surface completely without
overlaps or gaps.
Reflex angle: An angle
with a measure between
180o and 360o.
Polygon: A closed
plane figure with
straight sides.
Regular Polygon: A
polygon with all sides
being congruent and all
angles are congruent.
Tessellation Vertex: The
point where vertices meet
in a tessellation.
Right angle: An angle
that always measures 90
degrees—a square corner.
Right Triangle: A
triangle with one right
angle.
Straight angle: An
obtuse angle that
measures exactly 180
degrees.
Scalene Triangle: A
triangle with three
different sides and three
different angles.
Vertical angles: The
angles made by
intersecting lines that do
not share a common side.
Same as opposite angles.
Vertical angles have equal
measures.
Unit 3 Vocabulary Chart
