Question

notes of chapter 13 of class 9

Answer 1

Maths

1. Cuboid: A figure which is surrounded by six rectangular surfaces is called cuboid.

The opposite surface of a cuboid is equal and parallel.

A cuboid has 12 edges and 8 corners. Each corner of a cuboid is called the vertex of a cuboid. The line segment joining the opposite vertices is called the diagonal of a cuboid. There are four diagonals in a cuboid.

• Volume of cuboid = Length × Breadth × Height = l × b × h

• Lateral surface area = 2 (Length + Breadth) × Height = 2 (l + b) × h

• Total surface area = 2 (Length × Breadth + Breadth × Height + Height × Length) = 2 (lb + bh + hl)

• Total length of cuboid = 4 (l + b + h)