How many years does an El Nino happen?

it occurs irregularly at intervals of 2-7 years but the average is once every 3-4 years

Explanation:

hope this helped!

I think 3-7 years.

Explanation:

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