Question

how is 2[lb+bh+hl] formula made ​

Answer 1

Answer:

Refer to the explanation

Step-by-step explanation:

This formula is for total surface area of the cuboid

There are a total of 6 faces in a cuboid and each face is in a shape of a rectangle

Now we also know that opposite of each face is identical in a cuboid

The dimensions of a cuboid consists of 3 elements length (l) , breadth (b) and height (h)

each face will have either 2 of these 3 elements to form a rectangle

Now the area of a rectangle is given by A= product of 2 sides

So the combination for each face will be either of lb , bh, lh

we also know that there is an identical of each of these faces thus there area is also identical

which means to find the total surface area of a cuboid we need to add all the area of each face

Which will come out to be

TSA = lb+lb+bh+bh+lh+lh

TSA = 2lb +2bh+2lh

TSA = 2(lb+bh+lh) (hence proved)