A well of diameter 140 cm has a stone parapet around it. If the length of the outer edge of the parapet is 616 cm, find the width of the parapet. 

Answer

To find the width of the stone parapet around the well, we can follow these steps:

### Step 1: Find the radius of the well
The diameter of the well is given as 140 cm. The radius (r) is half of the diameter.

\[ r = \frac{\text{Diameter}}{2} = \frac{140 \text{ cm}}{2} = 70 \text{ cm} \]

### Step 2: Use the circumference of the outer edge of the parapet
The length of the outer edge of the parapet is given as 616 cm. This represents the circumference (C) of the larger circle formed by the parapet.

\[ C = 616 \text{ cm} \]

### Step 3: Use the formula for circumference to find the radius of the outer circle
The formula for the circumference of a circle is given by:

\[ C = 2\pi R \]

Where \( R \) is the radius of the outer circle (the well plus the parapet). We can rearrange this formula to solve for \( R \):

\[ R = \frac{C}{2\pi} \]

Substituting the values we have:

\[ R = \frac{616 \text{ cm}}{2 \times \frac{22}{7}} = \frac{616 \text{ cm} \times 7}{44} = \frac{4312}{44} = 98 \text{ cm} \]

### Step 4: Calculate the width of the parapet
The width of the parapet can be found by subtracting the radius of the well from the radius of the outer circle:

\[ \text{Width of the parapet} = R - r = 98 \text{ cm} - 70 \text{ cm} = 28 \text{ cm} \]

### Final Answer
The width of the parapet is **28 cm**.

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