Naming Angles Worksheet | PDF Printable Geometry Worksheet - Free Printable

Let’s go step by step through each angle in the table. We’ll estimate the size, name the type (acute, right, obtuse, reflex), and write the correct notation using the three letters given — with the vertex (corner point) in the middle.

---

Angle 1: DEF

- The angle at E looks a bit bigger than the example (35°). Maybe around 60°.
- It’s less than 90° → Acute
- Notation: Vertex is E → ∠DEF or ∠FED? Wait — standard is to put vertex in middle. Points are D-E-F, so angle at E is between D and F → ∠DEF

✔ Estimate: 60°, Type: Acute, Notation: ∠DEF

---

Angle 2: GHI

- Angle at H — very narrow, smaller than the example. Maybe 25°
- Less than 90° → Acute
- Vertex is H → points G-H-I → ∠GHI

✔ Estimate: 25°, Type: Acute, Notation: ∠GHI

---

Angle 3: JKL

- Angle at K — this one is wide open, more than 90° but not huge. Looks like 120°
- Between 90° and 180° → Obtuse
- Vertex is K → points J-K-L → ∠JKL

✔ Estimate: 120°, Type: Obtuse, Notation: ∠JKL

---

Angle 4: NMO

- Angle at M — there’s a full circle drawn around it! That means it’s the *reflex* angle — the big one going all the way around.
- A full circle is 360°, and the small part inside looks like maybe 70°, so reflex = 360 - 70 = 290°
- More than 180° → Reflex
- Vertex is M → points N-M-O → ∠NMO (but note: sometimes reflex angles are marked with an arc outside — here it’s shown as the large loop)

✔ Estimate: 290°, Type: Reflex, Notation: ∠NMO

Wait — actually, looking again: the arc is drawn on the *outside*, meaning they want the reflex angle. Yes.

---

Angle 5: PQR

- Angle at Q — very sharp, even narrower than GHI. Maybe 20°
- Acute
- Vertex Q → points P-Q-R → ∠PQR

✔ Estimate: 20°, Type: Acute, Notation: ∠PQR

---

Angle 6: STU

- Angle at T — looks like a right angle? But wait — no square symbol. Actually, it’s slightly less than 90°? Or maybe exactly 90°? Let’s check: lines look perpendicular. In worksheets like this, if it looks like a corner of a square, it’s often meant to be 90°.
- But let’s compare to next one — WVX has a square mark. This one doesn’t. Hmm.
Actually, looking closely: STU — the arms form what looks like a “V” that’s almost straight up-down-left-right. I think it’s intended to be 90°, even without the box. Many worksheets do that.
But to be safe — let’s say 90°, type Right, notation ∠STU

Wait — hold on. Let me double-check. In some curricula, if there’s no square, you don’t assume right angle. But visually, it’s very close. Alternatively, maybe it’s 85°? No — for estimation purposes, and since it’s clearly designed to be recognizable, I’ll go with 90°.

Actually — let’s look at the next one: WVX has a little square — that’s the official sign for right angle. So STU probably isn’t meant to be right. Looking again: from S to T to U — it’s opening upward, and the two sides seem symmetric. If I had to guess, maybe 80°? Still acute.

Better approach: Compare to known angles.

Example was 35°. GHI ~25°, PQR ~20°. STU is wider than those but not as wide as JKL (120°). Maybe 70°? Still acute.

I think safest is to call it Acute, estimate 70°, notation ∠STU

Wait — let’s count rows:

Row 1: DEF
Row 2: GHI
Row 3: JKL
Row 4: NMO
Row 5: PQR
Row 6: STU ← this is sixth row after example
Row 7: WVX
Row 8: ZYA
Row 9: ETP

So STU is sixth.

Looking at image again mentally: STU — vertex T, arms going down-left and down-right. The angle between them — if I imagine a clock, from 7 o’clock to 5 o’clock — that’s about 60°? Or 70°? Let’s say 70°, still acute.

✔ Estimate: 70°, Type: Acute, Notation: ∠STU

---

Angle 7: WVX

- Has a little square at W → that means exactly 90°
- Type: Right
- Vertex W → points V-W-X → ∠VWX (or ∠XWV — order matters? Usually we go in order around the angle. Standard is to list the points such that vertex is middle. So if the angle is formed by rays WV and WX, then it’s ∠VWX or ∠XWV — both acceptable, but typically we follow the diagram’s labeling. Diagram shows X above, V right, W bottom left. So likely ∠VWX or ∠XWV. But in the example, ABC was written with B in middle, and points A-B-C in order. Here, points are labeled X, W, V — so probably ∠XWV? Wait, the angle is at W, between X and V. So notation should be ∠XWV or ∠VWX. Either is fine, but let’s match the pattern: in example, it was ∠ABC where B is vertex, and A and C are endpoints. So here, vertex W, endpoints X and V → ∠XWV or ∠VWX. I think either is accepted, but to be consistent with how the points are listed in the diagram (X top, W corner, V right), perhaps ∠XWV.

Actually, in most textbooks, you can write it either way as long as vertex is in middle. Let’s use ∠VWX — because V and X are the outer points, W in middle.

But wait — the label says "W" at the vertex, "X" on vertical arm, "V" on horizontal. So the angle is between WX and WV. So notation: ∠XWV or ∠VWX. I’ll go with ∠VWX — same as example style.

✔ Estimate: 90°, Type: Right, Notation: ∠VWX

---

Angle 8: ZYA

- Angle at Y — there’s a circle around it again! Like NMO. So it’s the reflex angle.
- Small inner angle looks like maybe 60°, so reflex = 360 - 60 = 300°
- Type: Reflex
- Vertex Y → points Z-Y-A → ∠ZYA

✔ Estimate: 300°, Type: Reflex, Notation: ∠ZYA

---

Angle 9: ETP

- Angle at T — this one is also reflex? There’s an arc drawn on the outside, similar to NMO and ZYA.
- Inner angle looks like maybe 110°, so reflex = 360 - 110 = 250°
- Type: Reflex
- Vertex T → points E-T-P → ∠ETP

Wait — let’s confirm: points are E, T, P. Arc is drawn on the larger side, so yes, reflex angle.

Estimate: if inner is about 110°, reflex is 250°. Could be 240° or 260° — let’s say 250°

✔ Estimate: 250°, Type: Reflex, Notation: ∠ETP

---

Now let’s compile all answers into the table format.

Final Answer:

| Angle | Estimate | Type | Notation |
|-------|----------|----------|------------|
| DEF | 60° | ACUTE | ∠DEF |
| GHI | 25° | ACUTE | ∠GHI |
| JKL | 120° | OBTUSE | ∠JKL |
| NMO | 290° | REFLEX | ∠NMO |
| PQR | 20° | ACUTE | ∠PQR |
| STU | 70° | ACUTE | ∠STU |
| WVX | 90° | RIGHT | ∠VWX |
| ZYA | 300° | REFLEX | ∠ZYA |
| ETP | 250° | REFLEX | ∠ETP |

Note: For WVX, I used ∠VWX — but if your teacher prefers the order matching the diagram labels (X, W, V), you could write ∠XWV. Both are correct as long as W is in the middle. Since the example used ABC (not CBA), I followed the apparent direction: for WVX, starting from V to W to X, so ∠VWX is fine.

Also, estimates may vary slightly — these are reasonable guesses based on visual comparison to the 35° example and standard angle sizes.

──────────────────────────────────────

Final Answer:
DEF: 60°, ACUTE, ∠DEF
GHI: 25°, ACUTE, ∠GHI
JKL: 120°, OBTUSE, ∠JKL
NMO: 290°, REFLEX, ∠NMO
PQR: 20°, ACUTE, ∠PQR
STU: 70°, ACUTE, ∠STU
WVX: 90°, RIGHT, ∠VWX
ZYA: 300°, REFLEX, ∠ZYA
ETP: 250°, REFLEX, ∠ETP