Chapter 20: Mensuration Exercise 20.1

Question: 1

Which of the following are closed curves? Which of them are simple?

Solution:

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.

Solution:

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:

Solution:

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