Classify triangles by side lengths and angle measurements with this educational worksheet.

Let's solve the triangle classification problem step by step. We are asked to classify each triangle by side lengths and by angle measurements.

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🔹 Classification Rules:

#### By Side Lengths:
- Equilateral: All three sides are equal.
- Isosceles: Two sides are equal.
- Scalene: All sides are different.

#### By Angle Measurements:
- Acute: All angles are less than 90°.
- Right: One angle is exactly 90° (right angle).
- Obtuse: One angle is greater than 90°.

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Now, let’s analyze each triangle.

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## ✔ First Set (Top Table)

a.

- Image: A triangle with no marked sides equal, and one angle appears to be obtuse.
- Side Lengths: No sides marked as equal → Scalene
- Angles: One angle is clearly > 90° → Obtuse
- ✔ Answer: Scalene, Obtuse

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b.

- Image: Triangle with two sides marked with a single tick mark (equal), and a right angle symbol.
- Side Lengths: Two sides equal → Isosceles
- Angles: Has a right angle (square corner) → Right
- ✔ Answer: Isosceles, Right

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c.

- Image: Triangle with a right angle symbol (square corner).
- Side Lengths: No sides marked as equal → Scalene
- Angles: One right angle → Right
- ✔ Answer: Scalene, Right

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d.

- Image: A triangle with all sides appearing different in length, and one angle looks greater than 90°.
- Side Lengths: All sides different → Scalene
- Angles: One angle is obtuse → Obtuse
- ✔ Answer: Scalene, Obtuse

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## ✔ Second Set (Bottom Table)

a.

- Image: Triangle with a right angle symbol and no equal sides marked.
- Side Lengths: All sides appear different → Scalene
- Angles: One right angle → Right
- ✔ Answer: Scalene, Right

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b.

- Image: A triangle with no equal sides marked, and all angles look less than 90°.
- Side Lengths: All sides different → Scalene
- Angles: All angles < 90° → Acute
- ✔ Answer: Scalene, Acute

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c.

- Image: Triangle with two sides marked with a single tick (equal), and no right angle.
- Side Lengths: Two sides equal → Isosceles
- Angles: All angles appear less than 90° → Acute
- ✔ Answer: Isosceles, Acute

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d.

- Image: Triangle with all three sides marked with ticks (all equal).
- Side Lengths: All sides equal → Equilateral
- Angles: In equilateral triangles, all angles are 60° → Acute
- ✔ Answer: Equilateral, Acute

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🟩 Final Answers:

| Letter | Side Lengths | Angle Measurements |
|--------|------------------|--------------------|
| a | Scalene | Obtuse |
| b | Isosceles | Right |
| c | Scalene | Right |
| d | Scalene | Obtuse |

| Letter | Side Lengths | Angle Measurements |
|--------|------------------|--------------------|
| a | Scalene | Right |
| b | Scalene | Acute |
| c | Isosceles | Acute |
| d | Equilateral | Acute |

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✔ Summary of Key Concepts Used:
- Equilateral = all sides equal → always acute
- Isosceles = two sides equal
- Scalene = no sides equal
- Right = has a 90° angle
- Obtuse = one angle > 90°
- Acute = all angles < 90°

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