Geometry Worksheets | Angles Worksheets - Free Printable

Let’s go through each problem one by one. We’re classifying angles as acute, obtuse, right, or straight.

Here’s what each means:
- Acute angle: Less than 90°
- Right angle: Exactly 90° (looks like a corner of a square)
- Obtuse angle: More than 90° but less than 180°
- Straight angle: Exactly 180° (looks like a straight line)

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Part 1: Visual Angles (Problems 1–10)

We’ll look at the shape of each angle and decide based on how wide it opens.

1) Looks wider than 90°, not straight → obtuse
2) Very small, sharp point → acute
3) Wider than 90°, not straight → obtuse
4) Small, narrow opening → acute
5) Almost flat, very close to straight → straight (it’s drawn as a straight line with arrows)
6) Slightly more than 90° → obtuse
7) Wide open, clearly over 90° → obtuse
8) Very narrow, tiny angle → acute
9) Sharp, less than 90° → acute
10) Small, pointed angle → acute

Wait — let’s double-check #5. If it’s drawn as a straight line with two opposite rays, that’s a straight angle = 180° → yes, straight.

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Part 2: Degree Measures (Problems 11–20)

Now we use the numbers:

11) 84° → less than 90 → acute
12) 89° → still less than 90 → acute
13) 25° → way less → acute
14) 50° → less than 90 → acute
15) 180° → exactly straight → straight
16) 166° → between 90 and 180 → obtuse
17) 90° → exact right angle → right
18) 125° → between 90 and 180 → obtuse
19) 149° → also between 90 and 180 → obtuse
20) 106° → same range → obtuse

Double-checking all:

- Acute: <90 → 84, 89, 25, 50 → correct
- Right: =90 → only 90 → correct
- Obtuse: >90 and <180 → 166, 125, 149, 106 → correct
- Straight: =180 → only 180 → correct

Visual ones again:

1) obtuse ✔️
2) acute ✔️
3) obtuse ✔️
4) acute ✔️
5) straight ✔️
6) obtuse ✔️
7) obtuse ✔️
8) acute ✔️
9) acute ✔️
10) acute ✔️

All good.

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Final Answer:

1) obtuse
2) acute
3) obtuse
4) acute
5) straight
6) obtuse
7) obtuse
8) acute
9) acute
10) acute
11) acute
12) acute
13) acute
14) acute
15) straight
16) obtuse
17) right
18) obtuse
19) obtuse
20) obtuse