https://file.aiquickdraw.com/mathbot/file/17270978164163msn9a7b.jpg

Let's solve the problems one by one based on the image provided:

### Section 1:
**Given: \( \pi = 3.14 \)** and round answers to **1 decimal place (1 d.p.)**.

- **(a) \( d = 4 \, \text{cm} \)**  
  Formula: \( C = \pi d \)  
  Calculation: \( C = 3.14 \times 4 = 12.56 \, \text{cm} \)  
  Rounded: \( C = 12.6 \, \text{cm} \)

- **(b) \( d = 5 \, \text{cm} \)**  
  Formula: \( C = \pi d \)  
  Calculation: \( C = 3.14 \times 5 = 15.7 \, \text{cm} \)  
  Rounded: \( C = 15.7 \, \text{cm} \)

---

### Section 2:
**Given: \( \pi = 3.142 \)** and round answers to **2 decimal places (2 d.p.)**.

- **(a) \( d = 8 \, \text{cm} \)**  
  Formula: \( C = \pi d \)  
  Calculation: \( C = 3.142 \times 8 = 25.136 \, \text{cm} \)  
  Rounded: \( C = 25.14 \, \text{cm} \)

- **(b) \( d = 6 \, \text{cm} \)**  
  Formula: \( C = \pi d \)  
  Calculation: \( C = 3.142 \times 6 = 18.852 \, \text{cm} \)  
  Rounded: \( C = 18.85 \, \text{cm} \)

---

### Section 3:
Use the \( \pi \) button on the calculator for more accurate values. Round answers to **2 decimal places (2 d.p.)**.

- **(a) \( d = 9 \, \text{cm} \)**  
  Formula: \( C = \pi d \)  
  Calculation: \( C \approx 3.14159 \times 9 = 28.27431 \, \text{cm} \)  
  Rounded: \( C = 28.27 \, \text{cm} \)

- **(b) \( d = 12 \, \text{cm} \)**  
  Formula: \( C = \pi d \)  
  Calculation: \( C \approx 3.14159 \times 12 = 37.6991 \, \text{cm} \)  
  Rounded: \( C = 37.70 \, \text{cm} \)

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Would you like more details or have any questions about these calculations?

Here are 5 related questions to deepen your understanding:

1. How is the circumference of a circle related to its diameter?
2. How would the circumference change if the diameter is doubled?
3. What is the difference between using \( \pi = 3.14 \) and using the \( \pi \) button on a calculator?
4. Can you find the radius of the circle if you are given the circumference?
5. What would the circumference be if the diameter were 10 cm, using \( \pi \approx 3.14159 \)?

### Tip:
Always check whether you need to round your answers to a specific decimal place to avoid losing marks in exams!

Find the circumference of each circle using the given diameter and pi value.

Discover how to calculate the circumference of circles using the formulas C = πd. This lesson covers the application of pi in geometry to find the circumference, suited for students in grades 6-8.

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