Some people end up spending hours solving a single math problem, meanwhile, another person might solve it within seconds. The mere time difference comes out only because of the way that person thinks, out or inside the box.
Here is one such kind of problem that definitely drags you to think out of the box.
No textual explanation is given here, it sounds like the geometrical solid figures carry the pretty ensured details,
Rather than simply showering the paper with our little pen work, one can easily solve this by spotting the common features of the four figures.
The solution goes like this: