The Perimeter Calculator is a fundamental geometric tool used to determine the total length of the boundary of a two-dimensional shape. This calculation is essential for a wide variety of practical applications, such as figuring out the amount of fencing needed to enclose a garden, determining the length of trim required for a room, or planning a running track. This tool simplifies the process by providing the correct formulas for several common shapes. To use the calculator, begin by selecting the shape you are working with from the dropdown menu. The supported shapes include a Circle (where the perimeter is called the circumference), a Square, a Rectangle, and a Triangle. After you select a shape, the necessary input fields for its dimensions will appear. For a 'Circle', you will need to provide the 'Radius'. For a 'Square', you will enter the length of one 'Side'. For a 'Rectangle', you will be asked for both its 'Length' and 'Width'. For a 'Triangle', you will need to input the lengths of all three sides: 'Side A', 'Side B', and 'Side C'. After you've entered the required dimensions, click the 'Calculate Perimeter' button. The tool will instantly compute and display the total perimeter (or circumference) of the shape. This allows you to get fast and accurate measurements without having to manually apply the formulas yourself, making it a convenient resource for both educational and practical purposes.