Question

Without drawing a diagram, find (i) ${10}^{th}$ square number (ii) $6^{th}$ triangular number

Answer 1

Find ${10}^{th}$ square number and $6^{th}$ triangular number.

Now, ${10}^{th}$ square number is:

$$\begin{gathered} {10}^2=10\times 10 \\ =100 \end{gathered}$$

And $6^{th}$ triangular number is

$$\begin{gathered} =1+2+3+4+5+6 \\ =21 \end{gathered}$$

Thus, ${10}^{th}$ square number and $6^{th}$ triangular number is $100$ and $21$.