Table of Contents
Table of Contents
- Area of an Irregular Polygon
- Summary
- What’s Next?
In the previous segment, we learnt about the area of a trapezium. In this segment, we will learn how to find the area of a general polygon.
How to find the are of an irregular polygon?
We know that a polygon is a simple closed figure made up of only line segments. Based on the number of sides, a polygon is named a triangle, a quadrilateral, pentagon, hexagon and so on.
We have seen how to find the areas of a triangle and quadrilaterals like square and rectangle. We will now learn how to find the area of any polygon with help of a general quadrilateral.
Consider the quadrilateral ABCD.
Quadrilateral ABCD
Joining the opposite vertices A and C divides the quadrilateral into 2 triangles. Hence, Area (quadrilateral ABCD) = Area (triangle ABC) + Area (triangle ADC)
Area of quadrilateral ABCD
Formula for area of a triangle = ½ x base x height
AC is the common base for both triangles. Dropping perpendiculars BX and DY on to AC gives us the heights of triangles ABC and ADC respectively.