# Polygon Area and Perimeter calculator with points Polygon Area and Perimeter Calculator Number of Vertices Displayed Decimal Digits Vertex X Value Y Value 1 2 3 4 5 6 7 8 9 10 Perimeter Area

## Polygon Area and Perimeter calculator with points

To obtain the area and perimeter of a polygon, follow these steps:

1. Start at the top of the left column and assign a number, starting from 1, to each point as you proceed to the right column.
2. Enter the number of vertices in the designated form.
3. Enter the x and y values for each vertex of the polygon.
4. Once all the required data is entered, click the Calculate button to calculate the area and perimeter.
5. The calculated values will be displayed, using the specified number of decimal digits, including the coordinate values and the resulting area and perimeter.
6. Note that modifying the decimal digit display may alter the x and y coordinate values, potentially affecting the calculated area and perimeter.
7. In most practical scenarios, using 3 decimal digits is sufficient for accurate results.
8. Clicking the Reset button will clear the form's content and restore the default settings, setting the number of vertices and displayed decimal digits to 3.

Clicking the Reset button will erase the form's content and set the number of vertices and displayed decimal digits to 3.

## Defining a Polygon

A polygon is a two-dimensional geometric figure that is defined by a closed path consisting of straight line segments. It is formed by connecting a series of vertices with line segments, with each vertex represented by a set of coordinates (x, y) in a two-dimensional Cartesian plane.

The sides of a polygon are the line segments that connect consecutive vertices, and the vertices are the points where these line segments intersect. A polygon must have at least three sides and three vertices.

To calculate the area and perimeter of a polygon, we need to determine the lengths of its sides and the spatial arrangement of its vertices. The perimeter of a polygon is the sum of the lengths of its sides, while the area is the measure of the region enclosed by the polygon.

By analyzing the coordinates of the vertices, we can determine the lengths of the sides using the distance formula, which calculates the distance between two points in a Cartesian plane.

Understanding the properties and measurements of polygons is essential in various fields such as mathematics, architecture, computer graphics, and engineering. It allows for accurate calculations, spatial analysis, and geometric modeling.

## Calculating the Perimeter of a Polygon

Calculating the perimeter of a polygon involves determining the sum of the lengths of all its sides. Here's a step-by-step process to calculate the perimeter using the coordinates of the polygon's vertices:

1. Identify the coordinates of each vertex of the polygon: Each vertex is represented by a set of coordinates (x, y) in a two-dimensional Cartesian plane.

2. Compute the distance between consecutive vertices: Use the distance formula to find the length of each side. The distance formula calculates the distance between two points (x1, y1) and (x2, y2) as follows: distance = √((x2 - x1)^2 + (y2 - y1)^2).

3. Add up the distances: Sum up the lengths of all the sides by adding the computed distances together. The result will be the perimeter of the polygon.

For example, let's consider a polygon with four vertices: A(2, 4), B(5, 7), C(8, 4), and D(5, 1). To calculate its perimeter:

• Distance AB: √((5 - 2)^2 + (7 - 4)^2) = √(3^2 + 3^2) = √(18) ≈ 4.2426
• Distance BC: √((8 - 5)^2 + (4 - 7)^2) = √(3^2 + (-3)^2) = √(18) ≈ 4.2426
• Distance CD: √((5 - 8)^2 + (1 - 4)^2) = √((-3)^2 + (-3)^2) = √(18) ≈ 4.2426
• Distance DA: √((2 - 5)^2 + (4 - 1)^2) = √((-3)^2 + 3^2) = √(18) ≈ 4.2426

Perimeter = AB + BC + CD + DA = 4.2426 + 4.2426 + 4.2426 + 4.2426 = 16.9704

Therefore, the perimeter of the given polygon is approximately 16.9704 units.

By following these steps, you can accurately calculate the perimeter of a polygon using the coordinates of its vertices.

## Calculating the area of a polygon

Calculating the area of a polygon involves determining the measure of the region enclosed by the polygon. Here's a step-by-step process to calculate the area using the coordinates of the polygon's vertices, specifically using the shoelace formula (Gauss's area formula):

1. Arrange the coordinates of the vertices: Ensure that the coordinates are arranged in either a counterclockwise or clockwise order. This order is crucial for the accuracy of the result.

2. Multiply the x-coordinate of each vertex by the y-coordinate of the next vertex: Multiply the x-coordinate of the first vertex by the y-coordinate of the second vertex. Repeat this process for all vertices, except for the last one.

3. Multiply the y-coordinate of each vertex by the x-coordinate of the next vertex: Multiply the y-coordinate of the first vertex by the x-coordinate of the second vertex. Again, repeat this process for all vertices except the last one.

4. Add up the products obtained: Sum up all the products obtained in steps 2 and 3. This will result in two separate sums.

5. Divide the absolute value of the difference between the two sums by 2: Take the absolute value of the difference between the two sums obtained in step 4. Divide this absolute value by 2 to obtain the area of the polygon.

For example, let's consider a triangle with vertices A(1, 2), B(4, 5), and C(6, 1). To calculate its area using the shoelace formula:

• Multiply the x-coordinate of A (1) by the y-coordinate of B (5): 1 * 5 = 5

• Multiply the x-coordinate of B (4) by the y-coordinate of C (1): 4 * 1 = 4

• Multiply the x-coordinate of C (6) by the y-coordinate of A (2): 6 * 2 = 12

• Multiply the y-coordinate of A (2) by the x-coordinate of B (4): 2 * 4 = 8

• Multiply the y-coordinate of B (5) by the x-coordinate of C (6): 5 * 6 = 30

• Multiply the y-coordinate of C (1) by the x-coordinate of A (1): 1 * 1 = 1

• Sum of products from step 2: 5 + 4 + 12 = 21

• Sum of products from step 3: 8 + 30 + 1 = 39

• Absolute value of the difference: |21 - 39| = 18

• Area = 18 / 2 = 9 square units

Therefore, the area of the given triangle is 9 square units.

By following these steps and using the shoelace formula, you can accurately calculate the area of a polygon using the coordinates of its vertices.

## Formulas to find the perimeter and the area with points

Length of edge i = √ ( xi+1 - xi )² + ( yi+1 - yi

 n p = Σ √ ( xi+1 - xi )² + ( yi+1 - yi )² i=1

 n A = Σ | xi * yi+1 - yi * xi+1 | / 2 i=1

with xn+1 → x1 and yn+1 → y1

Calculating the area and perimeter of a polygon using points is a fundamental concept in geometry and has practical applications in various fields. By leveraging the coordinates of the polygon's vertices, we can accurately determine its area and perimeter using established formulas and methods. Whether you are a mathematician, architect, or computer graphics designer, understanding polygon calculations can aid in problem-solving and decision-making. By employing computer programs or online calculators, these calculations can be made more efficient and accessible to a wider audience.