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Lesson 5-1 Classifying Triangles
Lesson 5-1
Classifying Triangles
Ohio Content Standards:
Ohio Content Standards:
Formally define geometric figures.
Ohio Content Standards:
Establish the validity of conjectures about geometric objects, their properties and
relationships by counter-example, inductive and deductive reasoning, and critiquing
arguments made by others.
Ohio Content Standards:
Make and test conjectures about characteristics and properties
(e.g., sides, angles, symmetry) of two-dimensional figures and three-dimensional objects.
Triangle
Triangle
A figure formed when three noncollinear points
are connected by segments.
Acute Triangle
Acute Triangle
A triangle with all acute angles.
Obtuse Triangle
Obtuse Triangle
A triangle with one obtuse angle.
Right Triangle
Right Triangle
A triangle with one right angle.
Scalene Triangle
Scalene Triangle
A triangle with no sides congruent.
Isosceles Triangle
Isosceles Triangle
A triangle with at least two sides congruent.
Equilateral Triangle
Equilateral Triangle
A triangle with all sides congruent.
The angle formed by the congruent sides is called
the vertex angle.
The angle formed by the congruent sides is called
the vertex angle.
The side opposite the vertex angle is called the
base.
The angle formed by the congruent sides is called
the vertex angle.
The side opposite the vertex angle is called the
base.
base anglebase angle
The angle formed by the congruent sides is called
the vertex angle.
The side opposite the vertex angle is called the
base.
base anglebase angle
The two angles formed by the base
and one of the congruent sides are called base
angles.
The angle formed by the congruent sides is called
the vertex angle.
The side opposite the vertex angle is called the
base.
base anglebase angle
The two angles formed by the base
and one of the congruent sides are called base
angles.
legleg
The angle formed by the congruent sides is called
the vertex angle.
The side opposite the vertex angle is called the
base.
base anglebase angle
The two angles formed by the base
and one of the congruent sides are called base
angles.
legleg
The congruent sides are called
legs.
Classify each triangle by its angles and by its sides.
Classify each triangle by its angles and by its sides.
Classify each triangle by its angles and by its sides.
120°30°
30°
Find the measures of XY and YZ of isosceles triangle XYZ if
X is the vertex angle.
Y
X
Z
102n + 2
2n - 2
Assignment:
Pgs. 191-192 8-22 evens, 30-36 evens
