How to calculate the area of irregular shaped land or plot?/ Irregular shape site area calculation.( part-1 )

If you are looking for a readymade calculator, then click here.

For the calculation procedure, go through the following steps.👇

Now, let us go through some of the possible irregular shapes of the land or plot, and let us calculate the area of those plots, by using mathematical formulas.

Type 1 :

Here, two sides AD & BC are parallel to each other and all 4 sides have different lengths.

Given data :

 Side AD (a ) =  16.105m. 

  Side BC (b ) = 10m.

   Side AB = 7m.

   Side CD = 6.5m.

Side AD & BC of the land are parallel to each other.

The perpendicular distance between the side AD & BC ( h ) = 6m.

The area of the land is calculated by the formula

= 1/2 × ( a + b ) × h

= 1/2 × (side AD + side BC ) × Perpendicular distance 

= 1/2 × ( 16.105m + 10m ) × 6m

= 1/2 ×  26.105 m ×6m

= 78.315 sqm.

Note:

1. The formula should be used only when the two sides of the land are parallel to each other.

2.  The perpendicular distance between the two parallel sides, i.e. h can be measured directly on-plot, if not known.

Type 2:

Here, two sides AD & BC are parallel to each other & side DC is perpendicular to these two parallel sides.

Given data:

  Side AD (a ) =  13.6m. 

  Side BC (b ) = 10m.

  Side AB = 7m.

  Side CD ( h)= 6m.

Side AD & BC of the land are parallel to each other.

The area of the land is calculated by the formula

= 1/2 × ( a + b ) × h

= 1/2 × (side AD + side BC ) × side DC

= 1/2 × ( 13.6m + 10m ) × 6m

= 1/2 ×  23.6 m ×6m

= 70.8 sqm.

Note:

1. The formula should be used only when the two sides of the land are parallel to each other.

2.  There is no need to measure the length of the perpendicular distance, as side DC  joins the two parallel sides at a 90° angle.

Go through the article👇

👀. Area calculation for the irregular pentagon-shaped land. ( part- 3 )

Alternate method:

Let us draw a perpendicular line joining the sides AD & BC  as shown in the above drawing.

Side BE = side DC = 6m as both are perpendicular to the two parallel sides of the land.

Side AE = side AD - side BC 

            = 13.6m - 10m 

            = 3.6m.

Let us now calculate the area of triangle AEB and the area of rectangle EDBC separately 

Area of triangle AEB

   = 1/2 × base × height

  = 1/2 × side AE × side EB

= 1/2 × 3.6m × 6m

= 10.8 sqm.

Area of rectangle EDBC.

Here, length = side ED or side BC = 10m

        breadth = side EB or side DC = 6m.

Area of rectangle

    = length × breadth

    = 10m × 6m

   = 60 sqm.

Now, the area of the land 

= area of triangle AFB + area of rectangle EDBC

= 10.8 sqm. + 60 sqm.

 = 70.8 sqm.

(The answer is the same as above.)

Similarly, you can calculate and confirm the area of type 1 by making two triangles & one rectangle in the first drawing.

If you have any queries, you can ask me in the comment section.

         Continued 👉 Part 2

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