Download Types of Triangles

Types of Triangles
Geometry 3.6
Classification by Sides
with Flow Charts & Venn Diagrams
polygons
Polygon
triangles
Triangle
scalene
Scalene
Isosceles
isosceles
equilateral
Equilateral
2
Lesson 3-1: Triangle
Fundamentals
Classification by Angles
with Flow Charts & Venn Diagrams
Polygon
polygons
triangles
Triangle
right
acute
Right
Obtuse
Acute
Equiangular
3
equiangular
obtuse
Lesson 3-1: Triangle
Fundamentals
Types of Triangles by Lengths
of Sides.
M
Definition: SCALENE
a triangle in which no
sides are congruent.
O
N
Types of Triangles by Lengths
of Sides.
Vertex Angle A
Definition: ISOSCELES
a triangle in which at least
2 sides are congruent.
Leg
B
Leg
Base
Base Angles
C
Types of Triangles by Lengths
of Sides.
D
Definition: EQUILATERAL
a triangle in which all
sides are congruent.
E
**EQUILATERAL applies to any figure in
which all sides are congruent**
F
Types of Triangles by Lengths
of Sides.
An Equilateral Rectangle is
a SQUARE.
Types of Triangles by Size of
Angles.
Definition: ACUTE Triangle
a triangle in which all
angles are acute.
E
D
70
30
80
F
Types of Triangles by Size of
Angles.
Hypotenuse
Definition: RIGHT Triangle
a triangle in which one of B
the angles is a right angle.
Leg
A
Leg
C
Types of Triangles by Size of
Angles.
40
E
30
Definition: OBTUSE Triangle
a triangle in which one of
the angles is an obtuse
angle.
110 
F
D
Types of Triangles by Size of
Angles.
D
EQUIANGULAR:
a triangle in which all
angles are congruent.
60
60 60
F
E
**EQUIANGULAR applies to any figure in
which all angles are congruent**
C
Example:
Given: m<CBD = 70
70
A
B
Prove: Triangle ABC is obtuse
Proof: m<CBD = 70º and <ABD is a straight angle,
so m<ABC = 110º. Since ΔABC contains an obtuse
angle, it is an obtuse triangle.
D
Homework Help…#15
There are three possible diagrams
that satisfy this description.