Can you show me the way to find the square root of 112?

Deductive reasoning. Trial and error. You know that the square root of 112 will be roughly halfway between 10 and 11 because 112 is roughly halfway between 100 and 121.

10.5 x 10.5 = 110.25

10.58 x 10.58 = 111.9364

10.583 x 10.583 = 111.999889 which is close enough for me.