\begin{array}{l}
\text {Q1. Which of the following are closed curves? Which of them are simple? } \\
\end{array}\begin{array}{l}
\text {Sol. Figure (ii), (iii), (iv), (vi), and (vii) are closed curves.} \\
\text {Figure (ii), (iii), (iv) and (vi) are simple closed curves. }
\end{array}\begin{array}{l}
\text {Q2. Define perimeter of a closed figure. }
\end{array}\begin{array}{l}
\text {Sol. The length of the boundary of a closed figure is known as its perimeter.}
\end{array}\begin{array}{l}
\text {Q3. Find the perimeter of each of the following shapes:}
\end{array}\begin{array}{l}
\text {Sol. We know that perimeter is the sum of lengths of all the sides of a closed figure.} \\
\end{array}\begin{array}
\text {(i) Perimeter } =4+2+1+5=12 \text { cm} \\ \\
\end{array}\begin{array}
\text {(ii) Perimeter } =35 + 23 + 35 + 40=133 \text { cm} \\ \\
\end{array}\begin{array}
\text {(iii) Perimeter } =15+15+15+15=60 \text { cm} \\ \\
\end{array}\begin{array}
\text {(iv) Perimeter } =3+3+3+3+3=15 \text { cm} \\
\end{array}
