`A = f( "a" , "b" , "c" , "d" , "theta" )`

Enter a value for all fields

Area of Quadrilateral calculator computes the area of a simple quadrilateral given the four sides and the sum of opposing angles (a.k.a. Heron's quadrilateral).  

INSTRUCTIONS:  Choose units (e.g. inches or meters) and enter the following:     Simple Quadrilateral

• (a) - length of side a
• (b) - length of side b
• (c) - length of side c
• (d) - length of side d
• (θ) - the sum of any two opposite angles (θ = α+β). 

Area of a Quadrilateral (A): The calculator returns the area (A) in square meters. However, this can be automatically converted to many other area units (e.g. square inches) via the pull-down menu. 

Quadrilateral Calculators

• Area of a Quadrilateral from four sides and an angle
• Area of a Quadrilateral from four sides and the diagonal
• Quadrilateral Perimeter
• Quadrilateral Semi-Perimeter
• Quadrilateral Volume

The Math

Heron's formula is as follows:

   `Area = sqrt(( (a+b+c+d)/2-a)( (a+b+c+d)/2-b)( (a+b+c+d)/2-c)( (a+b+c+d)/2-d)-a*b*c*d * cos^2(θ"/"2) )`

where: 

• A is the area of the quadrilateral
• a, b, c, d are the lengths of the sides of the quadrilateral
• θ is one of the angles.

For other area calculators, see the following:

• Area of a Circle - Multiple functions to compute the area of a circle or portions of a circle.
• Area of Triangle -  Three Sides
• Area of Quadrilateral - Four Sides
• Area of Pentagon - Five Sides
• Area of Hexagon - Six Sides
• Area of Heptagon - Seven Sides
• Area of Octagon - Eight Sides
• Area of Nonogon - Nine Sides
• Area of Decagon - Ten Sides
• Area of Hendecagon - Eleven Sides
• Area of Dodecagon - Twelve Sides
• Area of Polygon  -  Any number of sides (n).