When you add two triangular numbers why do they equal to a square number?
They don't necesarily,3 is a triangular number and 10 is a triangular number. Their sum is 13 which is not a square number.They don't necesarily,3 is a triangular number and 10 is a triangular number. Their sum is 13 which is not a square number.They don't necesarily,3 is a triangular number and 10 is a triangular number. Their sum is 13 which is not a square number.They don't necesarily,3 is a triangular number and 10 is a triangular number. Their sum is 13 which is not a square number.