How do you determine the length of a circle (circumference) when rounding to the nearest tenth?

The length of a circle, commonly known as its circumference, can be calculated using the formula:

• C = 2 × π × r

In this formula:

• C represents the circumference.
• π (pi) is a mathematical constant approximately equal to 3.14159.
• r is the radius of the circle.

To find the circumference of a circle and round it to the nearest tenth, follow these steps:

1. Measure the radius of the circle. If you have the diameter instead, remember that the radius is half the diameter.

2. Substitute the radius value into the circumference formula. For example, if the radius is 5 units, the calculation would be:

   C = 2 × π × 5

3. Using the approximate value of π (3.14) for simplicity, calculate:

   C ≈ 2 × 3.14 × 5 = 31.4

4. Now, if your calculation gives you a more precise result, like 31.4159, round this number to the nearest tenth. In this case, since the digit after the first decimal (the second digit) is a ‘1’, you would round down to:

   31.4

5. However, if the calculation resulted in something like 31.678, the rounding would yield:

   31.7

And there you have it! The circumference, or the length of the circle, effectively rounded to the nearest tenth based on your radius measurement.