Summary  
This chapter demonstrates how to traverse a sequence of coordinate pairs with wrap-around indexing, compute the Euclidean distance between consecutive points, and sum those distances.  

General domain of usage  
Computational geometry


### 1. List the Vertices
A polygon is defined by a sequence of points (vertices) given as (`x`, `y`) coordinate pairs. For example, a triangle with vertices at (0, 0), (4, 0), and (4, 3) is represented as:

```python
triangle = [(0, 0), (4, 0), (4, 3)]
```



### 2. Calculate Distances Between Consecutive Vertices
To find the length of each side, use the distance formula between two points:

```python
distance = sqrt((x2 - x1)**2 + (y2 - y1)**2)
```
Loop through each pair of consecutive vertices and compute the distance.

### 3. Include the Closing Segment
After reaching the last vertex, connect it back to the first vertex. This ensures every side of the polygon is included in the perimeter calculation.

### 4. Sum All Distances
Add up all the distances to get the total perimeter.

#### For the triangle above:
- Distance from `(0, 0)` to `(4, 0)` is 4;
- Distance from `(4, 0)` to `(4, 3)` is 3;
- Distance from `(4, 3)` back to `(0, 0)` is 5.

Total perimeter: `4 + 3 + 5 = 12`.

By following these steps, you can calculate the perimeter of any polygon given its vertices in order.

from math import sqrt

def polygon_perimeter(vertices):
    """
    Compute the perimeter of a polygon given its vertices.

    Args:
        vertices (list of tuple): List of (x, y) tuples representing polygon vertices in order.

    Returns:
        float: Perimeter of the polygon.
    """
    perimeter = 0.0
    n = len(vertices)
    for i in range(n):
        x1, y1 = vertices[i]
        x2, y2 = vertices[(i + 1) % n]  # Wrap around to the first vertex
        distance = sqrt((x2 - x1)**2 + (y2 - y1)**2)
        perimeter += distance
    return perimeter

# Example usage:
triangle = [(0, 0), (4, 0), (4, 3)]
print("Triangle perimeter:", polygon_perimeter(triangle))

**Which of the following statements about polygon representation and perimeter calculation in Python is correct?**

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Calculating Polygon Perimeter

1. List the Vertices

2. Calculate Distances Between Consecutive Vertices

3. Include the Closing Segment

4. Sum All Distances

For the triangle above: