Identifying Types of Triangles - Determine if each triangle is acute, obtuse, or right and classify by side lengths

Sep 30, 2026

Uploaded by Fans

Worksheet content focused on identifying and classifying triangles by both angle measure and side-length relationships. Clear criteria define acute, obtuse, and right triangles using thresholds at 90°, along with equilateral, isosceles, and scalene categories based on equal side and equal angle counts. Several problems list triangle numbers for student classification, supported by an answer key that provides the corresponding letter codes for angle type (A/O/R) and side type (E/I/S).

LanguageEnglish

CategoryExam

FormatPDF

Pages3

Reading Time8 min

AccessFree to download

Determine triangle angle and side type

Angle-based classification (A, O, R)

Side-based classification (E, I, S)

Student items and answer key

Identifying Types of Triangles Name: | Determine if each triangle is acute(A), obtuse(O) or right(R) and if it is an

equilateral(E), isosceles(I) or scalene(S). Acute Triangle:
All angles are less than 90° .
Obtuse Triangle:
One angle is greater than 90° .
Right Triangle:
One angle is 90° .
Equilateral Triangle:
3 equal sides. 3 equal angles.
Isosceles Triangle:
2 equal sides. 2 equal angles.
Scalene Triangle:
No equal sides. No equal angles.

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8. | | Answers | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1-8 | 88 | 75 | 63 | 50 | | 38 | 25 | 13 | 0 | [Math](Math www.CommonCoreSheets.com 2)[ www.CommonCoreSheets.com](Math www.CommonCoreSheets.com 2)[ 2](Math www.CommonCoreSheets.com 2) Identifying Types of Triangles Name: Answer Key | Determine if each triangle is acute(A), obtuse(O) or right(R) and if it is an

equilateral(E), isosceles(I) or scalene(S). Acute Triangle:
All angles are less than 90° .
Obtuse Triangle:
One angle is greater than 90° .
Right Triangle:
One angle is 90° .
Equilateral Triangle:
3 equal sides. 3 equal angles.
Isosceles Triangle:
2 equal sides. 2 equal angles.
Scalene Triangle:
No equal sides. No equal angles.

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150
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188 | | | Answers 1. A S 2. A I 3. A E 4. O I 5. R S 6. O S 7. O I 8. R I | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 7)

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150 | | | | | | | | | | 1-8 | 88 | 75 | 63 | 50 | 38 | 25 | 13 | 0 | [Math](Math www.CommonCoreSheets.com 2)[ www.CommonCoreSheets.com](Math www.CommonCoreSheets.com 2)[ 2](Math www.CommonCoreSheets.com 2) Identifying Types of Triangles Name: | Determine if each triangle is acute(A), obtuse(O) or right(R) and if it is an

equilateral(E), isosceles(I) or scalene(S). Acute Triangle:
All angles are less than 90° .
Obtuse Triangle:
One angle is greater than 90° .
Right Triangle:
One angle is 90° .
Equilateral Triangle:
3 equal sides. 3 equal angles.
Isosceles Triangle:
2 equal sides. 2 equal angles.
Scalene Triangle:
No equal sides. No equal angles.

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6. | | Answers | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1-6 | 83 | 67 | | 50 | 33 | 17 | 0 | Math Modified [www.CommonCoreSheets.com](www.CommonCoreSheets.com) 2

FAQs

How do you identify an acute triangle?

An acute triangle has all angles less than 90°.

What makes a right triangle?

A right triangle has one angle that is exactly 90°.

How do you classify a scalene triangle?

A scalene triangle has no equal sides and no equal angles.

Sep 30, 2026

Uploaded by Fans