This calculator requires the use of Javascript enabled and capable browsers. It is to determine the area of an object. Select the object from the options, multiple triangles, square, circle, rectangle, rhombus, regular polygon and trapezium; then answer the questions about size, number of sides, radius, base, height, length or width for the object you wish to calculate. In regular or right triangles, the height is measured in a perpendicular from the highest point to the base. In irregular triangles, enter the length of each of the sides. Triangles do NOT need to be right triangles (though they can be); just select the correct calculator. All entries should be numeric. The answer is returned as a number, based on your entries. In the listed formulae for this set of calculations, PI here is used as 3.1415926535897932. Enjoy!.