Circle Review Worksheet: Area: A = πr Radius: 5.3 m Diameter: 10.6 ... - Free Printable

Let’s go through each circle one by one. We’ll find the radius, diameter, circumference, and area for each — just like in the example at the top.

We’re told to use 3.14 for π.

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Circle 1: Radius = 3 cm

- Radius = 3 cm (given)
- Diameter = 2 × radius = 2 × 3 = 6 cm
- Circumference = π × diameter = 3.14 × 6 = 18.84 cm
- Area = π × r² = 3.14 × (3)² = 3.14 × 9 = 28.26 cm²

✔ All correct except Area was left blank — now filled.

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Circle 2: Radius = 6 in

Wait — looking at the drawing, it shows a line from center to edge labeled “6 in” → that’s the radius, not diameter.

So:

- Radius = 6 in
- Diameter = 2 × 6 = 12 in
- Circumference = 3.14 × 12 = 37.68 in ✔ matches student
- Area = 3.14 × (6)² = 3.14 × 36 = 113.04 in² ✔ matches student

Good job here!

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Circle 3: Diameter = 9 mm (line goes all the way across)

So:

- Diameter = 9 mm
- Radius = 9 ÷ 2 = 4.5 mm ← Student wrote 9 mm — that’s wrong!
- Circumference = 3.14 × 9 = 28.26 mm ← Student wrote 56.52 — that’s double! Probably used diameter as radius.
- Area = 3.14 × (4.5)² = 3.14 × 20.25 = 63.585 mm² ← Student wrote 254.34 — way too big. They probably did 3.14 × 9² = 3.14 × 81 = 254.34 — but that’s if radius were 9, which it’s not.

⚠️ Correction needed here.

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Circle 4: Diameter = 4.8 cm (line across center)

- Diameter = 4.8 cm
- Radius = 4.8 ÷ 2 = 2.4 cm ✔
- Circumference = 3.14 × 4.8 = let’s calculate:
3.14 × 4 = 12.56
3.14 × 0.8 = 2.512
Total = 12.56 + 2.512 = 15.072 cm ✔
- Area = 3.14 × (2.4)² = 3.14 × 5.76
Let’s compute:
3 × 5.76 = 17.28
0.14 × 5.76 = 0.8064
Total = 17.28 + 0.8064 = 18.0864 cm² ✔

Perfect!

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Circle 5: Diameter = 7 cm

- Diameter = 7 cm
- Radius = 7 ÷ 2 = 3.5 cm ✔
- Circumference = 3.14 × 7 = 21.98 cm ✔
- Area = 3.14 × (3.5)² = 3.14 × 12.25
Compute:
3 × 12.25 = 36.75
0.14 × 12.25 = 1.715
Total = 36.75 + 1.715 = 38.465 cm² ✔

Great!

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Circle 6: Diameter = 14 cm

- Diameter = 14 cm
- Radius = 14 ÷ 2 = 7 cm ✔
- Circumference = 3.14 × 14 =
3.14 × 10 = 31.4
3.14 × 4 = 12.56
Total = 31.4 + 12.56 = 43.96 cm ✔
- Area = 3.14 × (7)² = 3.14 × 49
3 × 49 = 147
0.14 × 49 = 6.86
Total = 147 + 6.86 = 153.86 cm² ✔

Perfect!

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## Summary of Corrections Needed:

Only Circle 3 has errors:

Student wrote:
- Radius = 9 mm ✘ → should be 4.5 mm
- Circumference = 56.52 mm ✘ → should be 28.26 mm
- Area = 254.34 ✘ → should be 63.585 mm²

All others are correct!

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Final Answer:

Circle 1:
Radius = 3 cm, Diameter = 6 cm, Circumference = 18.84 cm, Area = 28.26 cm²

Circle 2:
Radius = 6 in, Diameter = 12 in, Circumference = 37.68 in, Area = 113.04 in²

Circle 3:
Radius = 4.5 mm, Diameter = 9 mm, Circumference = 28.26 mm, Area = 63.585 mm²

Circle 4:
Radius = 2.4 cm, Diameter = 4.8 cm, Circumference = 15.072 cm, Area = 18.0864 cm²

Circle 5:
Radius = 3.5 cm, Diameter = 7 cm, Circumference = 21.98 cm, Area = 38.465 cm²

Circle 6:
Radius = 7 cm, Diameter = 14 cm, Circumference = 43.96 cm, Area = 153.86 cm²