Question

what is diagonals?

Answer 1

the hypotenuse of a right triangle is a diagonal

Answer 2

the direction to opposite corners of a square are diagonals

Answer 3

you mean longest side?

Answer 4

no; a side is a side. in a right trianlge that would be true; but that doesnt define a diagonal

Answer 5

diagonals are only in rightangle triangle?

Answer 6

No; a right triangle has a diagonal from the tips of the legs; its called the hypotenuse in that case.

But a diagonal tends to span vertices that are not adjecent