Sitemap > Geometry > Quadrilateral Calculating the area of any quadrilateral Every quadrilateral is a polygon with four sides of any length connected together at the corners. The method of calculation for quadrilaterals is triangulation, which requires you to know the lengths of one of the two diagonals. Through this formula, it's possible to find out the area of any quadrilateral, no matter if it's a parallelogram, rhombus, trapezoid – in short, every 4-sided surface expect a crossed quadrilateral. Calculation of the quadrilateral Note: this form uses the triangulation calculation method. Quadrilateral * Be careful to respect the order of the sides and use the diagonal 'ab' as shown on the drawing, otherwise you may get a wrong result. Quadrilateral data: Units: milimeter centimeter decimeter meter decameter hectometer kilometer inch foot yard mile Side a: Side b: diagonal ab: Side c: Side d: Decimal places: 0 1 2 3 4 5 6 7 8 9 10 Units angles: Degrees Radians Gradians Quadrilateral results: Surface: 0,87 m^{2} Perimeter: 4,00 m Quadrilateral angles: (alfa) α : 60,00 ° (beta) β : 120,00 ° (gama) γ : 60,00 ° (delta) δ : 120,00 ° The Angles of a Quadrilateral Starting now, this page will show the value of the 4 angles. You can choose between degrees, radians or gradians. The calculation is done as follows: find the sum of the squares of the two adjacent sides of the angle, which is then subtracted from the square of the opposite diagonal. Then, divide the result of this "addition/subtraction" by the product of the two adjacent sides times two. Finally, you calculate the arccosine of the above result. What a cinch! Now for those who need it, you can find aspirin, Tylenol or other headache medicine at your nearest drug store… Quadrilaterals at Home Knowing the calculation of any quadrilateral is useful for determining the area of household objects with precision – even more so in older homes. It's common to have rooms in which the walls are not perpendicular with each other, making them not just rectangles, but various types of quadrilaterals. All the same, calculating the land surface area is very difficult if the surface is considered a rectangle, which is hardly ever the case. By knowing its four sides, one of its two diagonals and using the formula on this page, your results will be spot-on. Google Earth and Quadrilaterals By using the scale tool on Google Earth and filling in this formula, it's easy to find (very closely at least) the area of geographical locations which interest you. Crossed Quadrilaterals A quadrilateral may be convex (the usual case), concave (forming a recess) or crossed. In this last case, it creates two triangles. To calculate its features, the simplest way is to calculate the features of the two triangles which make up the crossed quadrilateral. List of calculation pages Construction Sizing stairs Calculate a slope, a gradient, a tilt Geometry The Cylinder The Triangle The slope, gradient, tilt The Parallelogram The Quadrilateral The Evolute Helix Maths Rule of three