What is the circumference of a 0.8 cm circle?
The correct answer and explanation is:
Okay, let’s calculate the circumference of the circle.
The Correct Answer:
The circumference of a 0.8 cm circle (assuming 0.8 cm is the diameter) is 0.8π cm, which is approximately 2.51 cm.
Explanation:
To find the circumference of a circle, which is the distance around its outer edge, we use a specific mathematical formula that relates the circumference to the circle’s diameter or radius. The most common formula for circumference (C) using the diameter (d) is:
C = πd
In this formula:
- C represents the Circumference.
- π (pi) is a special mathematical constant, approximately equal to 3.14159. It represents the ratio of a circle’s circumference to its diameter – meaning that for any circle, if you divide its circumference by its diameter, you always get the value of pi.
- d represents the Diameter, which is the distance straight across the circle passing through its center.
In your question, you have a “0.8 cm circle.” It’s standard convention in such cases to assume the given length is the diameter unless stated otherwise. So, we’ll assume the diameter (d) of this circle is 0.8 cm.
Now, we can plug this value into the formula:
C = π * 0.8 cm
Leaving the answer in terms of π gives us the exact circumference:
C = 0.8π cm
To get a numerical approximation, we use the approximate value of π (≈ 3.14159):
C ≈ 3.14159 * 0.8 cm
C ≈ 2.513272 cm
Rounding this to two decimal places, which is often sufficient given the precision of the input, we get:
C ≈ 2.51 cm
Therefore, the distance around a circle with a diameter of 0.8 cm is approximately 2.51 cm. The concept of pi is fundamental here, as it provides the constant link between the linear measure across a circle (diameter) and the distance around its curve (circumference).