Quais são as consequencias (positivas e negativas) da extração dos minerais metálicos

The metals have been used by the humans for several thousand years now, and ever since their usage was started they have had huge impact on the development of the human kind. In the present, the metals are used more than any time before. In order to get the metals though, they have to be extracted. This has its positives and negatives. The biggest positive is that the metals are essential part of the human lives, they are used in pretty much all fields, and are vital part of the economic and technological development. The biggest negative is that with the extraction of them, lot of damage is caused to the environment. The extraction itself means that lot of area has to be cleared of vegetation, there is lot of pollution from highly toxic chemicals which further destroy the surrounding vegetation and animals, and it also causes big pollution of the water and soil.

the answer would be the third option, "no, ariel should have added 9^2 and 12^2 and compared that to 15^2."

this is found through the pythagorean theorem, which is a^2 + b^2 = c^2.

this is the correct way of solving the problem:

9^2 + 12^2 = 15^2

81 + 144 = 225

225 = 225