4.2 Classifying Triangles.notebook
October 31, 2016
Chapter 4 Foldable
Classifying Triangles
&
Angles in Triangles
Special Triangles
&
Congruence
in
Triangles
Formulas
Classifying Triangles & Angles in Triangles
2
1 4 3
1 2
3 4
5 6
7 8
Linear Pairs (supplementary)
∠1 & ∠2 ∠2 & ∠3
∠3 & ∠4 ∠4 & ∠1
Vertical Angles (congruent)
∠1 & ∠3 ∠2 & ∠4
alternate interior angles (congruent)
∠3 & ∠6 ∠4 & ∠5
alternate exterior angles (congruent)
∠1 & ∠8 ∠2 & ∠7
consecutive (same-side) interior angles (supplementary)
∠3 & ∠5 ∠4 & ∠6
corresponding angles (congruent)
∠1 & ∠5 ∠2 & ∠6 ∠3 & ∠7 ∠4 & ∠8
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4.2 Classifying Triangles.notebook
October 31, 2016
What we will learn today:
• Classify triangles by their angle
measures and side lengths.
• Use triangle classification to find
angle measures and side lengths.
Triangles can be classified two ways
By their angle measures
Acute - all three angles are acute
Obtuse - one obtuse angle
Right - one right angle
Equiangular - all three angles are congruent
OR
By their side measures
Scalene – no congruent sides
Isosceles – two sides congruent
Equilateral – all three sides congruent
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4.2 Classifying Triangles.notebook
October 31, 2016
Example 1 ~ Classify
measures.
FHG by its angle
Example 2 ~ Classify
measures.
ABD by its angle
Example 3 ~ Classify
measures.
BCD by its angle
3
4.2 Classifying Triangles.notebook
October 31, 2016
Example 4 ~ Classify
FHG by its side measures.
Example 5 ~ Classify
FHE by its side measures.
Example 6 ~ Classify
measures.
ACD by its side
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4.2 Classifying Triangles.notebook
October 31, 2016
Example 7 ~ Find the value of x and the
measures of each side of the triangle.
Example 8 ~ Find the value of x and the
measures of each side of the equilateral FGH.
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