To solve the problem of finding the circumference of each circle using the given diameters, we use the formula for the circumference of a circle:
\[
C = \pi \times d
\]
where:
- \( C \) is the circumference,
- \( \pi \) (pi) is approximately 3.14159,
- \( d \) is the diameter of the circle.
We will calculate the circumference for each circle and round the answers to 1 decimal place.
Step-by-Step Calculations:
1.
Circle 1: Diameter = 5 cm
\[
C = \pi \times 5 \approx 3.14159 \times 5 = 15.70795 \approx 15.7 \text{ cm}
\]
2.
Circle 2: Diameter = 10 m
\[
C = \pi \times 10 \approx 3.14159 \times 10 = 31.4159 \approx 31.4 \text{ m}
\]
3.
Circle 3: Diameter = 3 cm
\[
C = \pi \times 3 \approx 3.14159 \times 3 = 9.42477 \approx 9.4 \text{ cm}
\]
4.
Circle 4: Diameter = 2 m
\[
C = \pi \times 2 \approx 3.14159 \times 2 = 6.28318 \approx 6.3 \text{ m}
\]
5.
Circle 5: Diameter = 8 mm
\[
C = \pi \times 8 \approx 3.14159 \times 8 = 25.13272 \approx 25.1 \text{ mm}
\]
6.
Circle 6: Diameter = 6 cm
\[
C = \pi \times 6 \approx 3.14159 \times 6 = 18.84954 \approx 18.8 \text{ cm}
\]
7.
Circle 7: Diameter = 9 m
\[
C = \pi \times 9 \approx 3.14159 \times 9 = 28.27431 \approx 28.3 \text{ m}
\]
8.
Circle 8: Diameter = 16 cm
\[
C = \pi \times 16 \approx 3.14159 \times 16 = 50.26544 \approx 50.3 \text{ cm}
\]
9.
Circle 9: Diameter = 12 mm
\[
C = \pi \times 12 \approx 3.14159 \times 12 = 37.69908 \approx 37.7 \text{ mm}
\]
10.
Circle 10: Diameter = 11 m
\[
C = \pi \times 11 \approx 3.14159 \times 11 = 34.55749 \approx 34.6 \text{ m}
\]
11.
Circle 11: Diameter = 20 cm
\[
C = \pi \times 20 \approx 3.14159 \times 20 = 62.8318 \approx 62.8 \text{ cm}
\]
12.
Circle 12: Diameter = 14 mm
\[
C = \pi \times 14 \approx 3.14159 \times 14 = 43.98226 \approx 44.0 \text{ mm}
\]
Final Answers:
\[
\boxed{
\begin{array}{lll}
1) & C = 15.7 \text{ cm} & \\
2) & C = 31.4 \text{ m} & \\
3) & C = 9.4 \text{ cm} & \\
4) & C = 6.3 \text{ m} & \\
5) & C = 25.1 \text{ mm} & \\
6) & C = 18.8 \text{ cm} & \\
7) & C = 28.3 \text{ m} & \\
8) & C = 50.3 \text{ cm} & \\
9) & C = 37.7 \text{ mm} & \\
10) & C = 34.6 \text{ m} & \\
11) & C = 62.8 \text{ cm} & \\
12) & C = 44.0 \text{ mm} & \\
\end{array}
}
\]
Parent Tip: Review the logic above to help your child master the concept of circumference worksheets.
