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Calculating 4-Side Irregular Quadrilateral Area

Area of Irregular Quadrilateral is calculated by knowing 4 sides and a angle or diagonal of it. This calculator useful for students, Engineers and anyone interested in calculating area of any real life four side object. We can also use it as irregular rectangle area calculator.

Enter 4 sides and an angle

Quadrilateral is 4-sided polygon. Irregular Quadrilateral is a quadrilateral that doesn’t fit into any of well-known form such as square, rectangle, parallelogram, rhombus and etc. Regular polygon has all sides and all angles are equal. Irregular quadrilateral is not a regular polygon.

Convex quadrilateral: All internal angles in the quadrilateral are less than 180 degrees.

Concave quadrilateral: One of internal angles is more than 180 degrees.

Check out the other geometry calculator for calculating circle chord and properties.

**How to use FineduCalcs Irregular Quadrilateral Area Calculator**

- Have the all sides and one angle information of irregular quadrilateral or measure all sides and any one angle of quadrilateral.
- Name the sides in serial starting with A and end with D. Also name the angle measured or known, as the sides between it is present.
- For example, Angle between sides B and C is named as BC, Diagonal between corners AB and CD is named as AB-CD.
- Enter the values of sides in the Calculator as per named A,B,C,D.
- Choose the Angle or Diagonal Name from drop down menu. Enter respective value below text field.
- The resultant Area of Irregular Quadrilateral or Irregular Rectangle is shown instantly by clicking Calculate button.

## Solving Area of irregular quadrilateral

This is a brief guide to calculate irregular quadrilateral area by own. Below for every input combination of irregular quadrilateral, how to calculate area is explained.

**Four sides and a Diagonal**

Quadrilateral can be divided into two triangles. Sum of two triangle areas is the area.

**Four sides and a angle **

If given angle is right angle, then using Pythagoras theorem diagonal is calculated. We are having two triangles and it is solved as in first scenario.

If given angle is less or more than 90 degrees.

- Consider the side for which a known angle is attached as base and draw diagonal opposite to known angle it forms a triangle.
- Denote base endpoints as first and second, the another endpoint of triangle as third. Draw a perpendicular line to base from third endpoint, name it as vertical line.
- Solve the vertical line using trigonometry as we know one angle and one side of triangle.
- Also solve base of right angle triangle that is formed with vertical line and diagonal of quadrilateral using trigonometry formulas.
- Now the hypotenuse of right angle triangle i.e. diagonal. Once diagonal is calculated then it become first scenario to calculate area of irregular quadrilateral with diagonal.

Check out the All in one circle calculator for area and perimeter.