Question

Which of the following is a triangular number?

(a) 2

(b) 4

(c) 5

(d) 6

This question was addressed to me during an internship interview.

This intriguing question comes from Properties of Squares in section Squares and Square Roots of Mathematics – Class 8

Answer 1

Correct choice is (d) 6

The best I can explain: Triangular numbers are the numbers which when arranged in increasing order forms a shape of triangle, the triangle shown represents the number 6. Hence the only number forming the triangular number is 6. Hence the options other than 6 are incorrect.