Geometry worksheet for classifying angles as acute, obtuse, right, straight, complementary, or supplementary.

Let’s go through each question one by one. We’re classifying angles as acute, obtuse, right, straight, or sometimes checking if two angles are complementary (add to 90°) or supplementary (add to 180°). But note: most of these show a single angle — so we’re mostly identifying the type of that single angle.

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Question 1:

Angle shown is less than 90° → acute

Options:
a. complementary
b. straight
c. acute ✔
d. right

→ Answer: c

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Question 2:

Angle has a square corner mark → that means it’s exactly 90° → right

Options:
a. right ✔
b. straight
c. acute
d. complementary

→ Answer: a

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Question 3:

Angle is wider than 90° but less than 180° → obtuse

Options:
a. right
b. supplementary
c. obtuse ✔
d. acute

→ Answer: c

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Question 4:

This shows TWO angles sharing a vertex, and together they form a right angle (90° total). So they are complementary.

Wait — let’s check: one ray goes left, one up, and one in between? Actually, looking at the diagram: there’s a horizontal line to the left, vertical up, and another ray between them. The angle between the left-pointing ray and the upward ray is 90°, and the middle ray splits it into two smaller angles. But the question is asking about the angle formed by the two outer rays? Or the whole thing?

Actually, re-examining: the figure shows three rays from a point: one pointing left, one pointing up, and one in between (closer to up). The angle being asked is likely the large angle from left to up — which is 90° → right? But wait, option “complementary” is there — which refers to *two* angles adding to 90°.

But the diagram doesn’t clearly label two separate angles — it just shows three rays. However, in many worksheets like this, when you see two adjacent angles forming a right angle, they want you to say “complementary”.

Looking again: the angle between the left ray and the middle ray, plus the angle between the middle ray and the top ray = 90°. So those two angles are complementary.

But the question says “classify the angle” — singular. Hmm.

Wait — perhaps the diagram is showing an angle that is made of two parts that add to 90°? Then the classification might be “complementary” meaning the pair.

But actually, looking at standard interpretation: if the diagram shows two angles next to each other making a right angle, then the correct term for their relationship is “complementary”.

So even though it's not a single angle, the context implies we’re to identify the relationship.

Given options include “complementary”, and the visual suggests two angles adding to 90°, I think the intended answer is:

→ b. complementary

But let me double-check with common worksheet patterns. In many cases, if two angles share a side and form a right angle together, they are called complementary.

Yes — so for Q4: b

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Question 5:

Two rays going out from a point, forming an angle less than 90° → acute

Options:
a. right
b. straight
c. acute ✔
d. complementary

→ Answer: c

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Question 6:

Three rays: one left, one right (so straight line), and one down-left. The angle between the left and right rays is 180° → straight

But wait — the diagram shows a point with rays: left, right, and down-left. The angle being measured is probably between the left and right rays — which is a straight line → 180° → straight

But option “straight” isn't listed! Wait:

Options:
a. complementary
b. supplementary
c. acute
d. right

Hmm — none say “straight”. That can’t be.

Wait — maybe it’s asking about the angle between the right ray and the down-left ray? That would be more than 90°, less than 180° → obtuse? Not listed either.

Alternatively — perhaps the two angles formed: one between left and down-left, and one between down-left and right — do they add to 180°? Yes — because left and right make a straight line. So any two adjacent angles on a straight line are supplementary.

Ah! That must be it. The diagram shows a straight line (left to right) with a third ray breaking it into two angles. Those two angles are supplementary (add to 180°).

So even though it’s not labeled, the relationship is supplementary.

→ Answer: b. supplementary

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Question 7:

Ray going left and ray going right — same line, opposite directions → 180° → straight

Options:
a. straight ✔
b. obtuse
c. supplementary
d. right

→ Answer: a

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Question 8:

Two rays: one down, one up-right. Angle between them looks greater than 90°, less than 180° → obtuse

Options:
a. complementary
b. straight
c. supplementary
d. obtuse ✔

→ Answer: d

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Question 9:

Vertical line (up and down) and a ray going up-right. So the angle between the downward ray and the up-right ray — that’s more than 90°, less than 180°? Wait — actually, from down to up-right: if up is 0°, down is 180°, up-right is say 45°, then from down (180°) to up-right (45°) going clockwise is 225° — too big. Better to take the smaller angle.

Actually, the angle formed at the vertex between the downward ray and the up-right ray — since the full circle is 360°, and the straight line is 180°, the angle between down and up-right should be 135° if up-right is 45° from vertical.

Wait — simpler: imagine a clock. Down is 6 o’clock, up-right is about 1:30. From 6 to 1:30 clockwise is 7.5 hours × 30° = 225° — no, better to take the smaller angle.

Actually, the angle between the downward ray and the up-right ray is the reflex? No — in geometry problems, unless specified, we take the smaller angle (<180°).

From down to up-right: if up is north, down is south, up-right is northeast. South to northeast is 135° (south to east is 90°, east to northeast is 45°, total 135°) → obtuse

But wait — options don’t have obtuse? Let’s see:

Options:
a. straight
b. acute
c. complementary
d. supplementary

None say obtuse. Hmm.

Perhaps it’s considering the two angles formed: the small one and the large one. The small angle between up and up-right is acute, but the diagram includes the downward ray.

Another thought: the vertical line (up-down) is 180°, and the up-right ray makes an acute angle with the upward part. So the angle between the upward ray and the up-right ray is acute, and the angle between the downward ray and the up-right ray is obtuse.

But the question is “classify the angle” — which angle? Probably the one drawn — which appears to be the angle between the downward ray and the up-right ray — which is obtuse.

But “obtuse” isn’t an option. Options are: straight, acute, complementary, supplementary.

Wait — perhaps they mean the relationship between the two angles formed: the acute angle (between up and up-right) and the obtuse angle (between down and up-right) — do they add to 180°? Yes! Because up and down are straight line.

So the two adjacent angles are supplementary.

That must be it. Even though only one angle is visually emphasized, the presence of the straight line implies we consider the pair.

So → d. supplementary

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Question 10:

Two rays: one up, one left-up. Angle between them is less than 90° → acute

Options:
a. supplementary
b. obtuse
c. complementary
d. acute ✔

→ Answer: d

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Now let’s compile all answers:

1. c
2. a
3. c
4. b
5. c
6. b
7. a
8. d
9. d
10. d

Double-check Q4 and Q6 and Q9 — they were tricky.

Q4: Two angles forming a right angle → complementary → b ✔️
Q6: Two angles on a straight line → supplementary → b ✔️
Q9: Two angles on a straight line (vertical) → supplementary → d ✔️

All good.

Final Answer:
1. c
2. a
3. c
4. b
5. c
6. b
7. a
8. d
9. d
10. d