Question 1. Which of the following are closed curves? Which of them are simple?
Figure (ii), (iii), (iv), (vi), and (vii) are closed curves, whereas Figure (ii), (iii), (iv) and (vi) are simple closed curves.
Question 2. Define perimeter of a closed figure.
The length of the boundary of a closed figure is known as its permieter.
Question 3. Find the perimeter of each of the following shapes:
Answer: Perimeter = Sum of lengths of all sides os a closed figure
(i) Perimeter = ( 4 + 2 + 1 + 5) cm = 12 cm
(ii) Perimeter = (23 + 35 + 40 + 35) cm = 133 cm
(iii) Perimeter = (15 + 15 + 15 + 15) cm = 60 cm
(iv) Perimeter = (3 + 3 + 3 + 3 + 3) cm = 15 cm