Circumference Practice Problems: Calculate Radius & Perimeter

Formula of the circumference:

$P=2\pi r$

We insert the given data into the formula:

$P=2\times6\times\pi$

$P=12\pi$

To solve this problem, we'll follow these steps:

• Step 1: Identify the formula for the circumference of a circle as $C = 2\pi r$.
• Step 2: Substitute the known value of the radius into the formula.
• Step 3: Simplify to find the circumference.

Now, let's work through each step:
Step 1: The formula for the circumference, $C$, is $C = 2\pi r$.
Step 2: Substitute the given radius $r = 3$ cm into the formula:
$C = 2\pi \times 3$.
Step 3: Perform the multiplication:
$C = 6\pi$.
Thus, the circumference of the circle is $6\pi$ cm.

Therefore, the solution to the problem is $6\pi$ cm.

The formula for the circumference is equal to:

$2\pi r$

To solve this problem, we'll follow these steps:

• Step 1: Identify the given information
• Step 2: Apply the appropriate formula
• Step 3: Perform the necessary calculations

Now, let's work through each step:
Step 1: The problem gives us the radius of the circle, $r = 2$.
Step 2: We'll use the formula for the circumference of a circle, which is $C = 2\pi r$.
Step 3: Substituting the radius into the formula, we get $C = 2 \times \pi \times 2 = 4\pi$.
Assuming $\pi$ is approximately 3.14, we calculate $C = 4 \times 3.14 = 12.56$.

Therefore, the circumference of the circle is $12.56$.

To solve this problem, follow these steps:

• Step 1: Given that the radius $r = 6$.
• Step 2: Use the formula for the circumference of a circle, $C = 2\pi r$.
• Step 3: Substitute the radius into the formula: $C = 2\pi \times 6$.
• Step 4: Calculate the expression: $C = 12\pi$.
• Step 5: Approximate $\pi \approx 3.14159$ to find $C \approx 12 \times 3.14159$.
• Step 6: Perform the multiplication: $C \approx 37.69908$.
• Step 7: Round off the number to three decimal places: $C \approx 37.699$.

The correct answer matches the choice labeled 2: 37.699.