The radius of the circular pipe is 13 cm. What length of a tape is required to warp around the pipe once ?

Answer

To find the length of tape required to wrap around a circular pipe once, we need to calculate the circumference of the circle. The formula for the circumference \( C \) of a circle is given by:

\[ C = 2 \pi r \]

where \( r \) is the radius of the circle.

### Step-by-Step Solution:

1. **Identify the radius**:
The radius of the circular pipe is given as \( r = 13 \) cm.

2. **Substitute the radius into the circumference formula**:
We use the formula for circumference:
\[ C = 2 \pi r \]
Substituting the value of \( r \):
\[ C = 2 \pi (13) \]
This simplifies to:
\[ C = 26 \pi \]

3. **Use the approximate value of \( \pi \)**:
We can use \( \pi \approx \frac{22}{7} \) for our calculations. Thus:
\[ C = 26 \times \frac{22}{7} \]

4. **Calculate the multiplication**:
First, calculate \( 26 \times 22 \):
\[ 26 \times 22 = 572 \]
Therefore, we have:
\[ C = \frac{572}{7} \]

5. **Perform the division**:
Now, divide \( 572 \) by \( 7 \):
\[ 572 \div 7 \approx 81.71428571428571 \]
Rounding this to two decimal places gives:
\[ C \approx 81.71 \text{ cm} \]

6. **Conclusion**:
The length of the tape required to wrap around the pipe once is approximately \( 81.71 \) cm.

### Final Answer:
The length of the tape required to wrap around the pipe once is \( 81.71 \) cm.

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