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Calculate volume, surface area, and diagonals of a rectangular prism (cuboid) by entering length, width, and height.
A rectangular prism (also called a cuboid or rectangular box) is a 3D shape with six rectangular faces. It has three different dimensions: length, width, and height.
A cube has all sides equal (l = w = h), while a cuboid can have three different dimensions. Every cube is a cuboid, but not every cuboid is a cube.
The space diagonal uses the 3D Pythagorean theorem: d = √(l² + w² + h²). It connects two vertices that are as far apart as possible.
A rectangular prism has three pairs of identical faces. Each pair has its own face diagonal based on the two dimensions that form that face.
Boxes, books, bricks, rooms, refrigerators, shipping containers, and most buildings are rectangular prisms.
If you know the volume and two dimensions, divide: missing = V ÷ (dimension₁ × dimension₂).
The longest straight object that fits inside is the space diagonal. For a box with dimensions l, w, h, this length is √(l² + w² + h²).