Notes On Surface Area of Solids - CBSE Class 8 Maths
Cube: A cube is a three-dimensional figure, a solid made up of six equal squares called faces. The lateral surface area (LSA) of a cube = 4l2. Total surface area (TSA) = 6l2. Cuboid: A cuboid is a solid made up of six rectangles, called faces. The total area of a cuboid is the sum of the areas of these faces. The lateral surface area (LSA) of a cuboid = 2h (l + b). Total surface area (TSA) = 2(lb + bh + hl). Cylinder: A cylinder is a solid composed of two congruent circles in parallel planes. Curved surface area (CSA) of a cylinderical pillar = 2πrh. Total surface area (TSA) = 2πr(r + h). Area of the four walls of a room = 2 x (l + b) x h = Perimeter of the floor x height. where l = length, b = breadth and h = height. Hollow cylinder A solid bounded by two coaxial cylinders of the same height and different radii is called a hollow cylinder. Surface area of each base = π(R2 - r2). Curved surface area (CSA) = 2πh(R + r). Total surface area (TSA) = 2π(R + r)(h + R - r), where R = external radius, r = internal radius and h = height.

#### Summary

Cube: A cube is a three-dimensional figure, a solid made up of six equal squares called faces. The lateral surface area (LSA) of a cube = 4l2. Total surface area (TSA) = 6l2. Cuboid: A cuboid is a solid made up of six rectangles, called faces. The total area of a cuboid is the sum of the areas of these faces. The lateral surface area (LSA) of a cuboid = 2h (l + b). Total surface area (TSA) = 2(lb + bh + hl). Cylinder: A cylinder is a solid composed of two congruent circles in parallel planes. Curved surface area (CSA) of a cylinderical pillar = 2πrh. Total surface area (TSA) = 2πr(r + h). Area of the four walls of a room = 2 x (l + b) x h = Perimeter of the floor x height. where l = length, b = breadth and h = height. Hollow cylinder A solid bounded by two coaxial cylinders of the same height and different radii is called a hollow cylinder. Surface area of each base = π(R2 - r2). Curved surface area (CSA) = 2πh(R + r). Total surface area (TSA) = 2π(R + r)(h + R - r), where R = external radius, r = internal radius and h = height.

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