RS Aggarwal Solutions: Mensuration - 6 | Mathematics (Maths) Class 7 PDF Download

 Page 1


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Question 1.  
 
 
Solution: 
(i) Radius of the circle (r) = 21 cm 
 
Question 2.  
 
 
Solution: 
(i) Diameter of the circle = 28 cm 
Page 2


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Question 1.  
 
 
Solution: 
(i) Radius of the circle (r) = 21 cm 
 
Question 2.  
 
 
Solution: 
(i) Diameter of the circle = 28 cm 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
 
 
Question 3.
  
Solution:
 
Circumference of a circle = 264 cm
 
 
Question 4.
  
Solution:
Circumference of the circle (c) = 35.2 m
Question 5.
Solution:
Area of the circle = 616 cm²
Page 3


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Question 1.  
 
 
Solution: 
(i) Radius of the circle (r) = 21 cm 
 
Question 2.  
 
 
Solution: 
(i) Diameter of the circle = 28 cm 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
 
 
Question 3.
  
Solution:
 
Circumference of a circle = 264 cm
 
 
Question 4.
  
Solution:
Circumference of the circle (c) = 35.2 m
Question 5.
Solution:
Area of the circle = 616 cm²
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Solution: 
Area of a circle = 1386 m² 
 
Question 7. 
 
Solution: 
Ratio in the radii of two circles = 4 : 5 
Let radius of first circle (r1) = 4x and radius of the second circle (r2) = 5x 
 
Question 6.
Page 4


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Question 1.  
 
 
Solution: 
(i) Radius of the circle (r) = 21 cm 
 
Question 2.  
 
 
Solution: 
(i) Diameter of the circle = 28 cm 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
 
 
Question 3.
  
Solution:
 
Circumference of a circle = 264 cm
 
 
Question 4.
  
Solution:
Circumference of the circle (c) = 35.2 m
Question 5.
Solution:
Area of the circle = 616 cm²
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Solution: 
Area of a circle = 1386 m² 
 
Question 7. 
 
Solution: 
Ratio in the radii of two circles = 4 : 5 
Let radius of first circle (r1) = 4x and radius of the second circle (r2) = 5x 
 
Question 6.
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Question 8.  
 
Solution: 
Length of rope (r) = 21 m 
Area of the circle = pr² = 22/7 x 21 x 21 m² = 1386 m² 
The horse will graze on 1386 m² area 
Question 9. 
 
Solution: 
Area of a square made of a wire = 121 cm² 
Side = vArea = v121 = 11 m 
Perimeter of wire = 4 x side = 4 x 11 = 44 cm 
Circumference of circular wire = 44 cm 
 
Question 10. 
 
Solution: 
Radius of circular wire = 28 cm 
Circumference = 2pr = 2 x 22/7 x 28 cm = 176 cm 
Perimeter of the square formed by this wire = 176 cm 
Side (a) = = 44 cm .
Area of square so formed = a² = (44)² cm² = 1936 cm²
Page 5


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Question 1.  
 
 
Solution: 
(i) Radius of the circle (r) = 21 cm 
 
Question 2.  
 
 
Solution: 
(i) Diameter of the circle = 28 cm 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
 
 
Question 3.
  
Solution:
 
Circumference of a circle = 264 cm
 
 
Question 4.
  
Solution:
Circumference of the circle (c) = 35.2 m
Question 5.
Solution:
Area of the circle = 616 cm²
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Solution: 
Area of a circle = 1386 m² 
 
Question 7. 
 
Solution: 
Ratio in the radii of two circles = 4 : 5 
Let radius of first circle (r1) = 4x and radius of the second circle (r2) = 5x 
 
Question 6.
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
Question 8.  
 
Solution: 
Length of rope (r) = 21 m 
Area of the circle = pr² = 22/7 x 21 x 21 m² = 1386 m² 
The horse will graze on 1386 m² area 
Question 9. 
 
Solution: 
Area of a square made of a wire = 121 cm² 
Side = vArea = v121 = 11 m 
Perimeter of wire = 4 x side = 4 x 11 = 44 cm 
Circumference of circular wire = 44 cm 
 
Question 10. 
 
Solution: 
Radius of circular wire = 28 cm 
Circumference = 2pr = 2 x 22/7 x 28 cm = 176 cm 
Perimeter of the square formed by this wire = 176 cm 
Side (a) = = 44 cm .
Area of square so formed = a² = (44)² cm² = 1936 cm²
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20F) Exercise 20F 
  
 
  
   
 
 
Question 11.
 
 
Solution:
 
Length of rectangular sheet (l) = 34 cm
 
and breadth (b) = 24 cm
 
Area = l x b = 34
 
x 24 cm² = 816 cm²
 
Diameter of one button = 3.5 cm
 
Radius (r) =3.5/2 cm
 
and area of one button = pr²
 
 
Area of 64 buttons = 9.625 x 64 cm² =616 cm²
 
Area of remaining sheet = 816 –
 
616 = 200 cm²
 
Question 12.
 
 
 
Solution:
Length of ground (l) = 90 m
and breadth (b) = 32 m
Area = l x b = 90 x 32 m² = 2880 m²
Radius of circular tank (r) = 14 m
= 616 m²
Area of remaining portion = 2880 – 616 = 2264 m²
Rate of turfing = Rs. 50 per sq.m.
Total cost = Rs. 50 x 2264 = Rs. 113200