Area of polygon
http://www.dummies.com/how-to/content/sizing-up-the-area-of-a-polygon.html
Perimeter of a shape which have different sides
Perimeter is the distance around an object. Add the measurements of the sides together.
To find the area of a polygon, you can use different methods depending on the type of polygon you have.
1. Triangles:
If you have a triangle, you can use the formula:
Area = (base * height) / 2
where the base is the length of the triangle's base and the height is the perpendicular distance from the base to the opposite vertex.
2. Rectangles:
For a rectangle, the formula is straightforward:
Area = length * width
where length represents the length of one side and width represents the length of the other side.
3. Squares:
The area of a square is found by:
Area = side length * side length
where each side has an equal length.
4. Regular polygons:
If you have a regular polygon (a polygon with all sides and angles equal), you can use the formula:
Area = (perimeter * apothem) / 2
where the perimeter is the total length of all sides and the apothem is the distance from the center of the polygon to a side (perpendicular).
5. Irregular polygons:
For irregular polygons, you can divide them into triangles, calculate the area of each triangle, and then sum them up to get the total area.
To calculate the area of irregular polygons using this method, follow these steps:
- Divide the polygon into triangles. Draw additional lines inside the polygon to create triangles.
- Calculate the area of each triangle using the triangle area formula mentioned above.
- Add up the areas of all the triangles to get the total area of the polygon.
Remember, the units for the area will depend on the units used for the measurements of the polygon's sides or dimensions.