Isosceles triangles may be obtuse or acute but never right?

False. They are right too.

They may be acute or obtuse, Yes.  But they could also be right-angled.

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)