\begin{tabular}{|l|l|l|}
\hline
\begin{tabular}{l}
4. [tex]$18^2$[/tex] \\
Ans.
\end{tabular} & \begin{tabular}{l}
5. [tex]$13^2$[/tex] \\
Ans.
\end{tabular} & \begin{tabular}{l}
6. [tex]$19^2$[/tex] \\
Ans.
\end{tabular} \\
\hline
\begin{tabular}{l}
7. [tex]$\sqrt{81}$[/tex] \\
Ans.
\end{tabular} & \begin{tabular}{l}
8. [tex]$\sqrt{196}$[/tex] \\
Ans.
\end{tabular} & \\
\hline
\end{tabular}



Answer :

Let's work through the steps to find the solutions for each of these problems:

### 4. [tex]\(18^2\)[/tex]
To find the square of 18, we calculate:
[tex]\[ 18 \times 18 = 324 \][/tex]
Ans. 324

### 5. [tex]\(13^2\)[/tex]
To find the square of 13, we calculate:
[tex]\[ 13 \times 13 = 169 \][/tex]
Ans. 169

### 6. [tex]\(19^2\)[/tex]
To find the square of 19, we calculate:
[tex]\[ 19 \times 19 = 361 \][/tex]
Ans. 361

### 7. [tex]\(\sqrt{81}\)[/tex]
To find the square root of 81, we ask what number multiplied by itself gives 81:
[tex]\[ \sqrt{81} = 9.0 \][/tex]
Ans. 9.0

### 8. [tex]\(\sqrt{196}\)[/tex]
To find the square root of 196, we ask what number multiplied by itself gives 196:
[tex]\[ \sqrt{196} = 14.0 \][/tex]
Ans. 14.0

Therefore, the answers are as follows:
- [tex]\(18^2 = 324\)[/tex]
- [tex]\(13^2 = 169\)[/tex]
- [tex]\(19^2 = 361\)[/tex]
- [tex]\(\sqrt{81} = 9.0\)[/tex]
- [tex]\(\sqrt{196} = 14.0\)[/tex]