Think about the different ecosystems we would find while studying the physical geography of the United States. Which ecosystem do you live in? In a short paragraph, describe the ecosystem that surrounds you. What kinds of plants and animals are common in your area?

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