Question

two cube of side 4cm are fixed together find the tsa of the new solid formed

Answer 1

T.S.A of cuboid is 2(lb+bh+hl)

Sides of the cuboid formed is 8,4,4 cm.

Therefore,the T.S.A is 2(32+16+32)
2(80)

$160 {cm}^{2}$

Answer 2

Hi friend,
I'll try to answer in the simplest way.
A cube has 6 faces.
When we combine 2 cubes to form a cuboid, 2 faces are eliminated since they're stick together.
So total faces of a cuboid=2×6 faces-2 eliminated faces

and area of a face=a²
so TSA of the new cuboid formed=10×a²=10a²
=10×4²=160cm²

Always imagine the concept instead of mugging up the formula.
All the best.......