Preview Warm Up California Standards Lesson Presentation

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Preview
Warm Up
California Standards
Lesson Presentation
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Warm Up 1. What is the name of a six-sided
polygon? 2. What is the definition of an acute
angle? 3. The measure of one of two
supplementary angles is 32. What is the measure
of the other angle?
hexagon
an angle that measures less than 90
148
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(No Transcript)
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Objective You will learn how to (YWLHT)
classify triangles by their side lengths and
angle measures.
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Vocabulary
scalene triangle isosceles triangle equilateral
triangle acute triangle obtuse triangle right
triangle
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One way to classify triangles is by the lengths
of their sides.
Triangles classified by sides
A scalene triangle has no congruent sides.
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One way to classify triangles is by the lengths
of their sides.
Triangles classified by sides
An isosceles triangle has at least 2 congruent
sides.
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One way to classify triangles is by the lengths
of their sides.
Triangles classified by sides
In an equilateral triangle, all of the sides are
congruent.
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One way to classify triangles is by the lengths
of their sides. Another way is by the measures of
their angles.
Triangles classified by angles
In an acute triangle, all of the angles are acute.
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One way to classify triangles is by the lengths
of their sides. Another way is by the measures of
their angles.
Triangles classified by angles
An obtuse triangle has one obtuse angle.
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One way to classify triangles is by the lengths
of their sides. Another way is by the measures of
their angles.
Triangles classified by angles
A right triangle has exactly one right angle.
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Example 1 Classifying Triangles
Classify each triangle according to its sides and
angles.
A.
Two congruent sides
isosceles
acute
Three acute angles
This is an isosceles acute triangle.
B.
scalene
No congruent sides
right
One right angle
This is a scalene right triangle.
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Example 2 Classifying Triangles
Classify each triangle according to its sides and
angles.
equilateral
C.
Three congruent sides
acute
Three acute angles
This is an equilateral acute triangle.
D.
No congruent sides
scalene
right
One right angle
This is a scalene right triangle.
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Check It Out! Example 3
Classify each triangle according to its sides and
angles.
isosceles
A.
Two congruent sides
obtuse
One obtuse angle
This is an isosceles obtuse triangle.
Two congruent sides
B.
isosceles
right
One right angle
This is an isosceles right triangle.
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Check It Out! Example 4
Classify each triangle according to its sides and
angles.
scalene
C.
No congruent sides
obtuse
One angle exceeding 90
This is a scalene obtuse triangle.
D.
No congruent sides
scalene
obtuse
One angle exceeding 90
This is a scalene obtuse triangle.
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Example 5 Identifying Triangles
Identify the different types of triangles in the
figure, and determine how many of each there are.
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Scalene
ABD,
CBD
Isosceles
2
ACE,
ABC
Right
2
ABD,
CBD
Obtuse
1
ACE
Acute
1
ABC
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Check It Out! Example 6
Identify the different types of triangles in the
figure, and determine how many of each there are.
A
Name
How many
Type
B
I
J
C
Isosceles
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D
H
F
2
G
Obtuse
E
Acute
4
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Home Learning
On-Line Tutoring
Geo-match-try
Geo-fit
Geo-Terms
Geo-Vocab
Shape Quiz
Angle Tangle
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Lesson Quiz
Classify each triangle according to its sides or
angles. 1. 7 ft, 8 ft, 12 ft 2. 45, 90,
45 3. 12, 9, 12 4. 120, 20, 40 5. Identify
the different types of triangles in the figure,
and determine how many of each there are.
scalene
right
isosceles
obtuse
1 isosceles acute triangle, 1 equilateral acute
triangle, 1 scalene right triangle