In the sequence of triangular numbers 1, 3, 6, 10,..., what is the sixth term?

In the sequence of triangular numbers 1, 3, 6, 10,..., what is the sixth term?

Question 1.

In the sequence of triangular numbers 1, 3, 6, 10,..., what is the sixth term?

Solution:

The sequence is 1, 3, 6, 10, 15, 21, 28, ...

So, the sixth term is 21.

Question 2.

What is the 12th term of the sequence of square numbers?

Solution:

First term = 1 × 1 = 1

Second term = 2 × 2 = 4

Third term = 3 × 3 = 9

So, 12 term = 12 × 12 = 144