How to use: Calculate area, perimeter, and volume of geometric shapes. Select Shape (Circle, Rectangle, or Sphere). Enter dimensions based on shape: Circle requires Radius, Rectangle requires Length and Width, Sphere requires Radius. Results show: Area (square units), Perimeter/Circumference (linear units), and Volume for 3D shapes (cubic units). Formulas: Circle area = πr², perimeter = 2πr. Rectangle area = length × width, perimeter = 2(length + width). Sphere volume = (4/3)πr³. Used for: construction measurements, land area calculations, material estimation, design planning, and space optimization. Essential for architecture, engineering, carpentry, and property surveying.