Which number is rational?
O √2
O π
O √10
O √16​

The only rational number in your list is "square 16" - I am assuming you mean square root of 16.
Explanation: Square root of 2 is irrational. This has been proven by the Pythagoreans (there is a simple proof of that).

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)