LSA (Lateral Surface Area) of a cuboid is the sum of the areas of its four lateral faces. It is also known as the surface area of the cuboid excluding the top and bottom faces. The formula for calculating the LSA of a cuboid is:

LSA = 2(hl + hb + lb)

Where,
h = height of the cuboid
l = length of the cuboid
b = breadth of the cuboid

Explanation:

The LSA of a cuboid is calculated by adding the areas of its four lateral faces. The lateral faces are the faces that are not the top or bottom faces. A cuboid has 4 lateral faces, and each face is a rectangle. The area of a rectangle is calculated by multiplying its length and breadth. Therefore, the LSA of a cuboid is calculated by adding the areas of all four rectangles.

Formula derivation:

The LSA of a cuboid can be derived by finding the sum of the areas of its four lateral faces. The lateral faces of a cuboid are all rectangles with different dimensions. Therefore, the formula for LSA can be expressed as:

LSA = Area of face 1 + Area of face 2 + Area of face 3 + Area of face 4

Where,
Area of face 1 = hl (the area of the face opposite to the length)
Area of face 2 = hb (the area of the face opposite to the breadth)
Area of face 3 = lb (the area of the face opposite to the height)
Area of face 4 = hl (the area of the face opposite to the length)

Adding all the areas, we get:

LSA = hl + hb + lb + hl

Simplifying the above equation, we get:

LSA = 2(hl + hb + lb)

Conclusion:

In conclusion, the LSA of a cuboid is the sum of the areas of its four lateral faces. The formula for LSA is 2(hl + hb + lb). It is important to note that the LSA does not include the top and bottom faces of the cuboid.