What is the circumference of a circle with a diameter of 13 cm to 1 decimal point?
A) 13.0 cm
B) 20.4 cm
C) 40.8 cm
D) 41.0 cm
The Correct answer and Explanation is :
The correct answer is: C) 40.8 cm
To find the circumference of a circle given its diameter, we can use the formula:
[
C = \pi \times d
]
where (C) is the circumference and (d) is the diameter of the circle. In this case, the diameter is 13 cm.
Step-by-Step Calculation:
- Identify the Diameter: The diameter (d) is given as 13 cm.
- Use the Formula: Plug the diameter into the formula for circumference:
[
C = \pi \times 13
] - Value of (\pi): The value of (\pi) (pi) is approximately 3.14159. For simplicity in calculation, we can use 3.14 or the more precise value as needed.
- Perform the Multiplication:
[
C \approx 3.14 \times 13 \approx 40.82 \text{ cm}
] - Round to One Decimal Point: To round 40.82 to one decimal point, we look at the second decimal place (2), which is less than 5. Therefore, we round down:
[
C \approx 40.8 \text{ cm}
]
Conclusion:
The circumference of a circle with a diameter of 13 cm is approximately 40.8 cm.
Answer:
Among the options provided:
- A) 13.0 cm
- B) 20.4 cm
- C) 40.8 cm
- D) 41.0 cm
The correct answer is C) 40.8 cm.
Understanding the relationship between diameter and circumference is crucial in geometry. The circumference provides insight into the circle’s size, affecting various practical applications, from engineering to art. Using this formula, one can easily calculate the circumference of any circle as long as the diameter is known.