If the diameter of a circle is 28 cm, then what will be its circumference (in cm)?

Options

A. 88
B. 176
C. 35
D. 70

Answer

To find the circumference of a circle when the diameter is given, we can follow these steps:

### Step 1: Identify the diameter
The diameter of the circle is given as 28 cm.

### Step 2: Calculate the radius
The radius (r) of a circle is half of the diameter.
\[ r = \frac{\text{diameter}}{2} = \frac{28 \text{ cm}}{2} = 14 \text{ cm} \]

### Step 3: Use the formula for circumference
The formula for the circumference (C) of a circle is:
\[ C = 2\pi r \]

### Step 4: Substitute the radius into the formula
Now, substitute the radius we found into the circumference formula:
\[ C = 2 \times \pi \times 14 \text{ cm} \]

### Step 5: Use the value of π
For calculations, we can use the approximation \(\pi \approx \frac{22}{7}\):
\[ C = 2 \times \frac{22}{7} \times 14 \text{ cm} \]

### Step 6: Simplify the expression
Now, calculate the expression:
\[ C = 2 \times \frac{22 \times 14}{7} \]
First, calculate \(22 \times 14\):
\[ 22 \times 14 = 308 \]
Now, substitute back:
\[ C = 2 \times \frac{308}{7} = \frac{616}{7} \text{ cm} \]
Now, divide 616 by 7:
\[ C = 88 \text{ cm} \]

### Final Answer
Thus, the circumference of the circle is **88 cm**.

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