Three-dimensional (3D) objects are solid shapes that have length, width, and height, making them occupy real space. They can have flat faces (like a cube or pyramid) or curved surfaces (like a sphere or cylinder) — or both. 3D shapes are made up of faces (surfaces), edges (where two faces meet), and vertices (corners where edges meet). Examples include: Sphere – One curved surface (e.g., ball, orange). Cube – 6 equal square faces (e.g., dice, ice cube). Cuboid – 6 rectangular faces (e.g., book, brick). Cone – 1 curved surface + 1 circular base (e.g., ice cream cone). Cylinder – 2 circular faces + 1 curved surface (e.g., can, pipe). Pyramid – Flat faces meeting at an apex (e.g., rooftop). Triangular Prism – 2 triangular faces + 3 rectangular faces (e.g., tent). 3D shapes can be unfolded into nets, which are flat patterns showing all faces that can be folded back into the solid. Understanding 3D objects helps in real-life applications such as design, architecture, engineering, and packaging.