Naming Angles Worksheet | PDF Printable Geometry Worksheet - Free Printable

Let's solve this step-by-step. The task is to estimate the size of each angle, identify its type, and write its notation (using the vertex and points on each side).

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🔍 Definitions to Remember:

- Acute angle: Less than 90°
- Right angle: Exactly 90°
- Obtuse angle: Between 90° and 180°
- Reflex angle: Greater than 180° but less than 360°
- Straight angle: Exactly 180°

Angle notation: ∠ + point at the vertex in the middle, e.g., ∠ABC means the angle at point B formed by points A, B, and C.

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Now, let’s go through each angle one by one.

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✔ Example (Given):

- Angle: ∠ABC
- Estimate: 35°
- Type: ACUTE
- Notation: ∠ABC

We'll follow the same format for all others.

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1. Angle DEF

- Diagram: Points D, E, F with angle at E.
- Estimate: Looks smaller than 45° — about 30°
- Type: ACUTE
- Notation: ∠DEF

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 30° | ACUTE | ∠DEF |

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2. Angle GIH

- Diagram: Points G, I, H; angle at I.
- Estimate: Very narrow — maybe around 20°
- Type: ACUTE
- Notation: ∠GIH

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 20° | ACUTE | ∠GIH |

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3. Angle JKL

- Diagram: Angle at K, between J and L.
- Estimate: Looks like it's around 100° — more than 90°, less than 180°
- Type: OBTUSE
- Notation: ∠JKL

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 100° | OBTUSE | ∠JKL |

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4. Angle NMO

- Diagram: Angle at M, with a small arc indicating reflex? Wait — look closely: there's a full circle mark at M, which indicates a reflex angle.
- But wait: the arc is less than half a circle, so actually, it’s more than 180°, but not full circle. It's a reflex angle.
- Estimate: Looks like about 240°
- Type: REFLEX
- Notation: ∠NMO

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 240° | REFLEX | ∠NMO |

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5. Angle RPQ

- Diagram: Angle at P, between R and Q.
- Estimate: Looks like a standard triangle angle — about 70°
- Type: ACUTE
- Notation: ∠RPQ

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 70° | ACUTE | ∠RPQ |

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6. Angle SUT

- Diagram: Angle at U, between S and T.
- Estimate: Looks like about 120°
- Type: OBTUSE
- Notation: ∠SUT

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 120° | OBTUSE | ∠SUT |

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7. Angle XWV

- Diagram: Right angle at W, with a square symbol.
- Estimate: Exactly 90°
- Type: RIGHT
- Notation: ∠XWV

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 90° | RIGHT | ∠XWV |

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8. Angle ZYA

- Diagram: Angle at Z, between Y and A.
- Estimate: Looks like about 140°
- Type: OBTUSE
- Notation: ∠ZYA

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 140° | OBTUSE | ∠ZYA |

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9. Angle TPE

- Diagram: Angle at P, between T and E.
- Estimate: Looks like it's over 180° — reflex angle.
- Estimate: About 220°
- Type: REFLEX
- Notation: ∠TPE

✔ Answer:
| Estimate | Type | Notation |
|----------|---------|----------|
| 220° | REFLEX | ∠TPE |

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✔ Final Table:

| Angle | Estimate | Type | Notation |
|-------|----------|---------|----------|
| DEF | 30° | ACUTE | ∠DEF |
| GIH | 20° | ACUTE | ∠GIH |
| JKL | 100° | OBTUSE | ∠JKL |
| NMO | 240° | REFLEX | ∠NMO |
| RPQ | 70° | ACUTE | ∠RPQ |
| SUT | 120° | OBTUSE | ∠SUT |
| XWV | 90° | RIGHT | ∠XWV |
| ZYA | 140° | OBTUSE | ∠ZYA |
| TPE | 220° | REFLEX | ∠TPE |

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📝 Notes:

- Estimates are approximations based on visual inspection.
- Always place the vertex letter in the middle when writing notation.
- Use the angle symbol (∠) before the letters.

Let me know if you'd like this formatted as a printable table or need help with measuring angles precisely!