Perimeter of a Circle - Free Printable

Problem Overview:

The task involves calculating the circumference of various circles given their diameters. The formula for the circumference \( C \) of a circle is:

\[
C = \pi \times d
\]

where:
- \( C \) is the circumference,
- \( \pi \) (pi) is approximately \( 3.14 \),
- \( d \) is the diameter of the circle.

We will use this formula to verify the provided answers for each circle.

---

Step-by-Step Solution:

#### 1. Circle with Diameter = 5 cm
\[
C = \pi \times d = 3.14 \times 5 = 15.7 \, \text{cm}
\]
Answer: Correct

#### 2. Circle with Diameter = 10 in
\[
C = \pi \times d = 3.14 \times 10 = 31.4 \, \text{in}
\]
Answer: Correct

#### 3. Circle with Diameter = 3 ft
\[
C = \pi \times d = 3.14 \times 3 = 9.4 \, \text{ft}
\]
Answer: Correct

#### 4. Circle with Diameter = 2 yd
\[
C = \pi \times d = 3.14 \times 2 = 6.3 \, \text{yd}
\]
Answer: Correct

#### 5. Circle with Diameter = 8 in
\[
C = \pi \times d = 3.14 \times 8 = 25.1 \, \text{in}
\]
Answer: Correct

#### 6. Circle with Diameter = 6 ft
\[
C = \pi \times d = 3.14 \times 6 = 18.8 \, \text{ft}
\]
Answer: Correct

#### 7. Circle with Diameter = 9 cm
\[
C = \pi \times d = 3.14 \times 9 = 28.3 \, \text{cm}
\]
Answer: Correct

#### 8. Circle with Diameter = 16 ft
\[
C = \pi \times d = 3.14 \times 16 = 50.3 \, \text{ft}
\]
Answer: Correct

#### 9. Circle with Diameter = 12 in
\[
C = \pi \times d = 3.14 \times 12 = 37.7 \, \text{in}
\]
Answer: Correct

#### 10. Circle with Diameter = 11 yd
\[
C = \pi \times d = 3.14 \times 11 = 34.6 \, \text{yd}
\]
Answer: Correct

#### 11. Circle with Diameter = 20 in
\[
C = \pi \times d = 3.14 \times 20 = 62.8 \, \text{in}
\]
Answer: Correct

#### 12. Circle with Diameter = 14 ft
\[
C = \pi \times d = 3.14 \times 14 = 44.0 \, \text{ft}
\]
Answer: Correct

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Final Answer:

All the provided answers are correct. The circumferences match the calculations using the formula \( C = \pi \times d \).

\[
\boxed{\text{All answers are correct.}}
\]