Practice: Measuring Angles and Using a Protractor and More ... - Free Printable

Let’s go step by step to measure each angle using a protractor (as if we’re doing it on paper). Since we can’t actually use a physical protractor here, we’ll estimate based on standard angle types and visual clues — but in real homework, you’d place the protractor’s center on the vertex and read where the other side crosses the scale.

We are told to:
- Measure each angle in degrees.
- Write the type of angle (acute, obtuse, right, straight).

Recall:
- Acute = less than 90°
- Right = exactly 90°
- Obtuse = more than 90° but less than 180°
- Straight = exactly 180°

Now let’s analyze each one:

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Problem 1:
Looks like an acute angle — smaller than a right angle. Probably around 45°.
Type: Acute

Problem 2:
This is clearly wider than 90°, looks like about 135°.
Type: Obtuse

Problem 3:
This is a half-circle — that’s a straight line. So 180°.
Type: Straight

Problem 4:
Perfect corner — looks like a right angle. 90°.
Type: Right

Problem 5:
Very small angle — maybe 30°.
Type: Acute

Problem 6:
Wider than 90°, not quite 180° — probably 150°.
Type: Obtuse

Problem 7:
Small again — similar to #5, maybe 30° or 40°. Let’s say 30°.
Type: Acute

Problem 8:
Almost a full circle minus a small slice — this is a reflex? Wait — no, looking at the arc, it goes from one ray all the way around past 180° to almost 360°. But wait — in basic geometry for students, they usually only ask up to 180° unless specified. However, the arc drawn suggests it's measuring the *larger* angle — which would be reflex, but since the worksheet doesn't list "reflex" as a type, and the example angles shown at top are only acute, obtuse, straight, right — perhaps this is meant to be measured as the smaller angle? No — look at the arc: it starts at the bottom ray and sweeps counterclockwise all the way around to the left ray — that’s more than 180°. Actually, let me reconsider.

Wait — in many elementary worksheets, even if the arc draws the large angle, they still expect you to measure the interior angle between the two rays — which would be the smaller one. But in problem 8, the two rays form a very narrow angle — so the actual angle between them is small — maybe 30° — but the arc is drawn going the long way. That might be confusing.

Actually, looking again: In problem 8, the two rays are close together — forming a small angle — but the curved arrow goes the long way around. That usually means they want the reflex angle — but since “reflex” isn’t listed in the types above, and the instructions say “use the information on page 39” (which we don’t have), we must assume they want the smaller angle between the rays — because otherwise, we can’t classify it with given types.

But wait — let’s check the drawing carefully. The vertex is at the bottom. One ray points down-left, the other points down-right — very close together. The arc starts at the left ray and goes clockwise all the way around to the right ray — passing through top — meaning it’s measuring the big angle — which is 360° minus the small angle. If the small angle is 30°, then the big one is 330° — but again, “reflex” isn’t an option.

Alternatively — maybe the arc is just indicating direction, and we’re to measure the angle inside the V-shape — which is small. Given that problems 5 and 7 are also small acute angles, and 8 looks similar, I think it’s safe to assume they want the interior angle — so 30°, acute.

BUT — hold on! Look at problem 3: it has a semicircle arc over a straight line — that’s clearly 180°. Problem 8 has an arc that covers most of the circle — suggesting it’s meant to be measured as the large angle. However, since the worksheet does NOT include “reflex” as a category, and the student is expected to choose from acute, obtuse, straight, right — then perhaps problem 8 is misdrawn, or we’re supposed to measure the smaller angle.

Actually — let’s think differently. Maybe in problem 8, the two rays are almost overlapping — so the angle between them is tiny — say 10°–30° — and the arc is just showing rotation direction. In that case, we measure the smallest angle between the two rays — which is acute.

I think for consistency with the rest, and since “reflex” isn’t an option, we’ll go with the smaller angle.

So:

Problem 8: Small angle — 30°, Type: Acute

Wait — but let me double-check problem 6 and 2 — those are clearly obtuse. Problem 3 is straight. Problem 4 is right. Problems 1,5,7,8 are all acute — that seems plausible.

Alternatively, maybe problem 8 is meant to be 330° — but again, no “reflex” type. So likely, the teacher expects the smaller angle.

Another possibility: sometimes in such diagrams, if the arc goes the long way, they want the reflex — but since it’s not in the types, perhaps it’s a trick? Unlikely for this level.

I think safest assumption: measure the angle between the two rays — the smaller one — regardless of arc direction — unless the arc is over a straight line (like #3) or right angle (#4).

So final estimates:

1. 45° — Acute
2. 135° — Obtuse
3. 180° — Straight
4. 90° — Right
5. 30° — Acute
6. 150° — Obtuse
7. 30° — Acute
8. 30° — Acute

But wait — problem 8’s rays are even closer than #5 and #7? Maybe 20°? But without exact tool, 30° is reasonable.

Alternatively, perhaps problem 8 is 330° — but again, no classification. So I’ll stick with 30° acute.

Actually — let me look again at the original image description (even though I shouldn’t describe it — but for reasoning): user said “the image contains a task” — and from context, problem 8 has an arc that wraps almost all the way around — which in some curricula means they want the reflex angle — but since it’s not in the types, perhaps it’s a mistake? Or maybe I should consider that the angle is 360° - x, and x is small — but again, no reflex.

Perhaps the intended answer for #8 is 330° — but what type? Not listed. So unlikely.

Another idea: maybe the arc in #8 is just poorly drawn, and they mean the small angle. I think for a 4th/5th grader, they’d expect the small angle.

Final decision:

All answers based on visual estimation and standard expectations for this level.

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Final Answer:
1. 45°, Acute
2. 135°, Obtuse
3. 180°, Straight
4. 90°, Right
5. 30°, Acute
6. 150°, Obtuse
7. 30°, Acute
8. 30°, Acute