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 Page 1


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Question 1. 
 
Solution: 
In parallelogram ABCD, 
Base AB = 32cm 
Height DL = 16.5cm. 
 
Area = Base x height = 32 x 16.5 cm² = 528 cm² 
Question 2.
 
.
 
Solution:
 
Base of parallelogram = 1 m 60m = 160 cm
 
and height = 75 cm
 
Area = Base x height = 160 x 75 = 12000 cm²
 
= 12001/ 10000 m² = 1.2m²
 
 
 
 
Page 2


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Question 1. 
 
Solution: 
In parallelogram ABCD, 
Base AB = 32cm 
Height DL = 16.5cm. 
 
Area = Base x height = 32 x 16.5 cm² = 528 cm² 
Question 2.
 
.
 
Solution:
 
Base of parallelogram = 1 m 60m = 160 cm
 
and height = 75 cm
 
Area = Base x height = 160 x 75 = 12000 cm²
 
= 12001/ 10000 m² = 1.2m²
 
 
 
 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Solution: 
Base of parallelogram = 14dm = 140cm 
and height = 6.5 dm = 65cm 
Area (in cm²) = Base x height = 140 x 65 = 9100 cm² 
Area (in m²) = 140/100x 65/100 = 9100/10000 
= 0.91 m² 
Question 4. 
 
Solution: 
Area of parallelogram = 54 cm² 
Base = 15 cm 
 
Question 5. 
 
Solution:
Area of parallelogram ABCD = 153 cm²
Question 3.
Page 3


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Question 1. 
 
Solution: 
In parallelogram ABCD, 
Base AB = 32cm 
Height DL = 16.5cm. 
 
Area = Base x height = 32 x 16.5 cm² = 528 cm² 
Question 2.
 
.
 
Solution:
 
Base of parallelogram = 1 m 60m = 160 cm
 
and height = 75 cm
 
Area = Base x height = 160 x 75 = 12000 cm²
 
= 12001/ 10000 m² = 1.2m²
 
 
 
 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Solution: 
Base of parallelogram = 14dm = 140cm 
and height = 6.5 dm = 65cm 
Area (in cm²) = Base x height = 140 x 65 = 9100 cm² 
Area (in m²) = 140/100x 65/100 = 9100/10000 
= 0.91 m² 
Question 4. 
 
Solution: 
Area of parallelogram = 54 cm² 
Base = 15 cm 
 
Question 5. 
 
Solution:
Area of parallelogram ABCD = 153 cm²
Question 3.
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
 
 
 
Question 6.
  
  
 
Solution:
 
In parallelogram ABCD
 
AB || DC and AD || BC and AB = DC, AD = BC
 
AB = DC = 18cm, BC = 12cm
 
Area of parallelogram ABCD = Base x altitude = DC x AL = 18 x 6.4cm2 
= 115.2 cm²
 
and area of parallelogram ABCD = BC x AM
? 115.2 = 12 x AM
? AM = 9.6 cm
Question 7.
Solution:
In parallelogram ABCD
AB = DC = 15 cm
BC = AD = 8 cm.
Distance between longer sides AB and DC is 4cm
i.e. perpendicular DL = 4cm.
DM ? BC.
Area of parallelogram = Base x altitude = AB x DL = 15 x 4 = 60 cm²
Again let DM = x cm
area ABCD = BC x DM = 8 x x = 8x cm²
8x cm² = 60 cm²
? x = 7.5 cm
Distance between shorter lines = 7.5 cm
Page 4


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Question 1. 
 
Solution: 
In parallelogram ABCD, 
Base AB = 32cm 
Height DL = 16.5cm. 
 
Area = Base x height = 32 x 16.5 cm² = 528 cm² 
Question 2.
 
.
 
Solution:
 
Base of parallelogram = 1 m 60m = 160 cm
 
and height = 75 cm
 
Area = Base x height = 160 x 75 = 12000 cm²
 
= 12001/ 10000 m² = 1.2m²
 
 
 
 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Solution: 
Base of parallelogram = 14dm = 140cm 
and height = 6.5 dm = 65cm 
Area (in cm²) = Base x height = 140 x 65 = 9100 cm² 
Area (in m²) = 140/100x 65/100 = 9100/10000 
= 0.91 m² 
Question 4. 
 
Solution: 
Area of parallelogram = 54 cm² 
Base = 15 cm 
 
Question 5. 
 
Solution:
Area of parallelogram ABCD = 153 cm²
Question 3.
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
 
 
 
Question 6.
  
  
 
Solution:
 
In parallelogram ABCD
 
AB || DC and AD || BC and AB = DC, AD = BC
 
AB = DC = 18cm, BC = 12cm
 
Area of parallelogram ABCD = Base x altitude = DC x AL = 18 x 6.4cm2 
= 115.2 cm²
 
and area of parallelogram ABCD = BC x AM
? 115.2 = 12 x AM
? AM = 9.6 cm
Question 7.
Solution:
In parallelogram ABCD
AB = DC = 15 cm
BC = AD = 8 cm.
Distance between longer sides AB and DC is 4cm
i.e. perpendicular DL = 4cm.
DM ? BC.
Area of parallelogram = Base x altitude = AB x DL = 15 x 4 = 60 cm²
Again let DM = x cm
area ABCD = BC x DM = 8 x x = 8x cm²
8x cm² = 60 cm²
? x = 7.5 cm
Distance between shorter lines = 7.5 cm
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Solution: 
Let Base of the parallelogram = x 
 
? x² = 108 x 3 = 324 = (18)² 
? x = 18 
Base = 18 cm 
and altitude = x 18 = 6 cm 
Question 9.
 
 
Solution:
 
Area of parallelogram = 512 cm²
 
Let height of the parallelogram
 
= x
 
Then base = 2x
 
Area = Base x height
 
?
 
512 = 2x x x
 
?
 
2x² = 512
 
?
 
x² = 256 = (16)²
 
?
 
x = 16
 
Base = 2x = 2 x 16 = 32 cm
 
and height = x = 16 cm
 
  
 
  
Question 8.
Page 5


RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Question 1. 
 
Solution: 
In parallelogram ABCD, 
Base AB = 32cm 
Height DL = 16.5cm. 
 
Area = Base x height = 32 x 16.5 cm² = 528 cm² 
Question 2.
 
.
 
Solution:
 
Base of parallelogram = 1 m 60m = 160 cm
 
and height = 75 cm
 
Area = Base x height = 160 x 75 = 12000 cm²
 
= 12001/ 10000 m² = 1.2m²
 
 
 
 
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Solution: 
Base of parallelogram = 14dm = 140cm 
and height = 6.5 dm = 65cm 
Area (in cm²) = Base x height = 140 x 65 = 9100 cm² 
Area (in m²) = 140/100x 65/100 = 9100/10000 
= 0.91 m² 
Question 4. 
 
Solution: 
Area of parallelogram = 54 cm² 
Base = 15 cm 
 
Question 5. 
 
Solution:
Area of parallelogram ABCD = 153 cm²
Question 3.
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
 
 
 
Question 6.
  
  
 
Solution:
 
In parallelogram ABCD
 
AB || DC and AD || BC and AB = DC, AD = BC
 
AB = DC = 18cm, BC = 12cm
 
Area of parallelogram ABCD = Base x altitude = DC x AL = 18 x 6.4cm2 
= 115.2 cm²
 
and area of parallelogram ABCD = BC x AM
? 115.2 = 12 x AM
? AM = 9.6 cm
Question 7.
Solution:
In parallelogram ABCD
AB = DC = 15 cm
BC = AD = 8 cm.
Distance between longer sides AB and DC is 4cm
i.e. perpendicular DL = 4cm.
DM ? BC.
Area of parallelogram = Base x altitude = AB x DL = 15 x 4 = 60 cm²
Again let DM = x cm
area ABCD = BC x DM = 8 x x = 8x cm²
8x cm² = 60 cm²
? x = 7.5 cm
Distance between shorter lines = 7.5 cm
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Solution: 
Let Base of the parallelogram = x 
 
? x² = 108 x 3 = 324 = (18)² 
? x = 18 
Base = 18 cm 
and altitude = x 18 = 6 cm 
Question 9.
 
 
Solution:
 
Area of parallelogram = 512 cm²
 
Let height of the parallelogram
 
= x
 
Then base = 2x
 
Area = Base x height
 
?
 
512 = 2x x x
 
?
 
2x² = 512
 
?
 
x² = 256 = (16)²
 
?
 
x = 16
 
Base = 2x = 2 x 16 = 32 cm
 
and height = x = 16 cm
 
  
 
  
Question 8.
RS Aggarwal Solutions Class 7 Chapter 20 - Mensuration  (Ex 20C) Exercise 20C 
  
 
  
   
Solution:
 
(i) Each side of rhombus = 12 cm
 
height = 7.5 cm
 
 
Area = Base x height = 12 x 7.5 = 90 cm²
 
(ii) Each side = 2 cm = 20 cm
 
Height = 12.6 cm
 
Area = Base x height = 20 x 12.6 = 252 cm²
 
Question 11.
 
 
 
 
Question 10.
Solution:
(i) Diagonals of rhombus ABCD are 16 cm and 28 cm
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