Grade 5 Geometry Worksheets: Circumference of circles | Worsheets library - Free Printable

To find the circumference of a circle, we use the formula:

Circumference = π × diameter
or
Circumference = 2 × π × radius

Since all the problems give us either the diameter (a line across the circle through the center) or the radius (half the diameter), we can use the right formula.

We’ll use π ≈ 3.14 for all calculations unless told otherwise.

Let’s solve each one step by step.

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Problem 1: Diameter = 36 yd

Circumference = π × diameter = 3.14 × 36
→ 3.14 × 36 = let’s calculate:

3 × 36 = 108
0.14 × 36 = 5.04
Total = 108 + 5.04 = 113.04 yd

✔ Check: 3.14 × 36 = 113.04 → correct.

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Problem 2: Radius = 12 ft

First, diameter = 2 × radius = 2 × 12 = 24 ft
Circumference = π × diameter = 3.14 × 24

3 × 24 = 72
0.14 × 24 = 3.36
Total = 72 + 3.36 = 75.36 ft

✔ Check: 3.14 × 24 = 75.36 → correct.

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Problem 3: Diameter = 14 in

Circumference = 3.14 × 14

3 × 14 = 42
0.14 × 14 = 1.96
Total = 42 + 1.96 = 43.96 in

✔ Check: 3.14 × 14 = 43.96 → correct.

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Problem 4: Radius = 15 in

Diameter = 2 × 15 = 30 in
Circumference = 3.14 × 30 = 94.2 in

✔ Check: 3.14 × 30 = 94.2 → correct.

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Problem 5: Diameter = 8 in

Circumference = 3.14 × 8 = 25.12 in

✔ Check: 3.14 × 8 = 25.12 → correct.

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Problem 6: Diameter = 8 yd

Same as problem 5 but units are yards.

Circumference = 3.14 × 8 = 25.12 yd

✔ Correct.

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Problem 7: Diameter = 18 in

Circumference = 3.14 × 18

3 × 18 = 54
0.14 × 18 = 2.52
Total = 54 + 2.52 = 56.52 in

✔ Check: 3.14 × 18 = 56.52 → correct.

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Problem 8: Diameter = 10 yd

Circumference = 3.14 × 10 = 31.4 yd

✔ Correct.

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Problem 9: Diameter = 4 yd

Circumference = 3.14 × 4 = 12.56 yd

✔ Correct.

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Final Answer:
1. 113.04 yd
2. 75.36 ft
3. 43.96 in
4. 94.2 in
5. 25.12 in
6. 25.12 yd
7. 56.52 in
8. 31.4 yd
9. 12.56 yd