Download 2b Angle Properties Dictionary with Definitions for Angles 12

Angle
Vertex
Degree
Straight, Reflex, Obtuse, Acute, Right Angles
Supplementary Angle
Complementary Angle
Opposite Angle
Adjacent Angle
Triangle Angle Sum (Interior Angles of a Triangle)
Isosceles Triangle
Equilateral Triangle
Exterior Angle of a Triangle
Parallel lines with a transversal
Corresponding Angles
Alternate Interior Angles
Same Side Interior
Word
(Short Form or Symbol)
Angle
Vertex

Degree

Straight Angle
Definition
(Textbook and My Own)
A shape, formed by two lines or
rays diverging from a common
point (the vertex).
Diagram
ACB or BCA
The vertex is the common point
at which the two lines or rays
are joined.
A unit for measuring angles, the
rotation between two lines.
Measurements are often
expressed as a number followed
by the symbol °
(=180°) FDC
Reflex Angle
(>180°) =BDE
Obtuse Angle
(<180° and >90°) =CDE
Acute Angles
(<00°) =BDC
Right Angle
(=90°) =ADF
DFE=35 GFD=145
Video or Web Resource
Word and
Short Form
Adjacent Angles
Definition
(Textbook and My Own)
Diagram
Two angles that are formed
when one angle is divided into
two parts by a straight line.
BDF and BDC are Adjacent
Supplementary
Angles
(Supp.)
Two or more angles that make
180° when they are added
together.
BDF and BDC are Supp.
Complementary
Angles
(Comp.)
Two or more angles that
together form a right angle.
BDA and BDC are Comp.
Opposite Angles
(Opp.)
The angles opposite each other
that are formed when two lines
intersect. The angles are equal.
LKO and JKM are Opp.
LKJ and MKO are Opp.
Video or Web Resource
Word and
Short Form
Triangle Angle
Sum
(TAS)
Definition
(Textbook and My Own)
Diagram
All three angles in a triangle
always add up to 180.
a + b + c =180
Isosceles
Triangle
(IT)
Equilateral
Triangle
(ET)
External Angles
of a Triangle
(EAT)
Two sides are equal and two
angles are equal. The equal
angles are opposite to the equal
sides.
All the sides are equal and all the
angles are equal. All angles equal
60.
Look at picture. The sum of the
two internal angles is equal to
the external angle of a triangle.
a + b = c
Video or Web Resource