Is sixty a triangular number

Answer 1

Yes, sixty is a triangular number. Triangular numbers are those that can form an equilateral triangle, and they follow the formula ( T_n = \frac{n(n+1)}{2} ). For ( n = 10 ), ( T_{10} = \frac{10 \times 11}{2} = 55 ) and for ( n = 11 ), ( T_{11} = \frac{11 \times 12}{2} = 66 ). Therefore, sixty is not a triangular number, as it falls between the triangular numbers 55 and 66.