A number is called a triangular number if its dot pattern can be arranged in
a rectangle
a triangle
a rectangle and a line
a triangle and a rectangle
A number is called a triangular number if its dot pattern can be arranged in a triangle.
Question 19 By using dot (.) patterns, which of the following numbers can be arranged in all the three ways namely a line, a triangle and a rectangle? (A) 9 (B) 10 (C) 11 (D) 12