Classifying Triangles

Classify using angle measurements.

Groups:

(a) Right

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(b) Obtuse

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(c) Acute

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Classify by using side lengths.

Groups:

(a) Equilateral

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(b) Isosceles

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(c) Scalene

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Match the following definitions to the correct vocabulary term.

• A triangle with only 2 congruent sides.

• Equilateral Triangle

• A triangle that has no equal sides.

• Isosceles Triangle

• A triangle that has all congruent sides.

• Scalene Triangle

The triangles have been classified by a shared attribute (side length or angle type). Use one of the words acute, right, obtuse, scalene, isosceles, or equilateral to label the headings to identify the way the triangles have been sorted.

c

b

d

Scalene

Isosceles

Acute

Right

Obtuse

Equilateral

Evaluate responses using AI:

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If the perimeter of an equilateral triangle is 15 cm, what is the length of each side?

Mathematical Equivalence

ON

Identify each triangle according to side length.

• Isosceles

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• Equilateral

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• Scalene

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A student used this graphic organizer to classify different figures.

Which figures belong in the part of the organizer labeled "Isosceles triangles"?

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Triangles can be classified in 2 ways:

By their angles: acute, right, or obtuse

By their sides: equilateral, isosceles, scalene

Select all the ways the triangle can be classified.

• Acute

• Scalene

• Obtuse

• Equilateral

• Isosceles