Selina Textbook Solutions: Recognition of Solids | Mathematics Class 6 ICSE PDF Download

 Page 1


EXERCISE 31 
Question 1. 
Identify the nets which can be used to form cubes : 
 
Solution: 
Nets for a cube are (ii), (iii) and (iv). 
Question 2. 
Draw at least three different nets for making cube. 
Solution: 
 
Question 3. 
The dimensions of a cuboid are 6 cm, 4 cm and 3 cm. Draw two different types of 
oblique sketches for this cuboid. 
Solution: 
 
Page 2


EXERCISE 31 
Question 1. 
Identify the nets which can be used to form cubes : 
 
Solution: 
Nets for a cube are (ii), (iii) and (iv). 
Question 2. 
Draw at least three different nets for making cube. 
Solution: 
 
Question 3. 
The dimensions of a cuboid are 6 cm, 4 cm and 3 cm. Draw two different types of 
oblique sketches for this cuboid. 
Solution: 
 
Question 4. 
Two cubes, each with 3 cm edge, are placed side by side to form a cuboid. For 
this cuboid, draw : 
(i) an oblique sketch 
(ii) an isometric sketch. 
Solution: 
 
 
Question 5. 
The figure, given below, shows shadows of some 3D objects, when seen under 
the lamp of an overhead projector : 
 
Page 3


EXERCISE 31 
Question 1. 
Identify the nets which can be used to form cubes : 
 
Solution: 
Nets for a cube are (ii), (iii) and (iv). 
Question 2. 
Draw at least three different nets for making cube. 
Solution: 
 
Question 3. 
The dimensions of a cuboid are 6 cm, 4 cm and 3 cm. Draw two different types of 
oblique sketches for this cuboid. 
Solution: 
 
Question 4. 
Two cubes, each with 3 cm edge, are placed side by side to form a cuboid. For 
this cuboid, draw : 
(i) an oblique sketch 
(ii) an isometric sketch. 
Solution: 
 
 
Question 5. 
The figure, given below, shows shadows of some 3D objects, when seen under 
the lamp of an overhead projector : 
 
In each case, name the object. 
Solution: 
 
Question 6. 
Look at the solids, drawn below, and fill the given chart. 
 
Solution: 
 
P. Q. Using Euler’s formula, find the values of a, b, c and d. 
 
Page 4


EXERCISE 31 
Question 1. 
Identify the nets which can be used to form cubes : 
 
Solution: 
Nets for a cube are (ii), (iii) and (iv). 
Question 2. 
Draw at least three different nets for making cube. 
Solution: 
 
Question 3. 
The dimensions of a cuboid are 6 cm, 4 cm and 3 cm. Draw two different types of 
oblique sketches for this cuboid. 
Solution: 
 
Question 4. 
Two cubes, each with 3 cm edge, are placed side by side to form a cuboid. For 
this cuboid, draw : 
(i) an oblique sketch 
(ii) an isometric sketch. 
Solution: 
 
 
Question 5. 
The figure, given below, shows shadows of some 3D objects, when seen under 
the lamp of an overhead projector : 
 
In each case, name the object. 
Solution: 
 
Question 6. 
Look at the solids, drawn below, and fill the given chart. 
 
Solution: 
 
P. Q. Using Euler’s formula, find the values of a, b, c and d. 
 
Solution: 
 
(i) a + 6 — 12 = 2 ?a = 2- 6+12 = 14-6 = 8 
(ii) b + 5- 9 = 2 ?b-2 + 9-5 = 6 
(iii) 20 + 12 – c = 2 ? 32 – c = 2 ? c = 32 – 2 ? c = 30 
(iv) 6 + d – 12 = 2 ? d-6 = 2 ? d = 2 + 6 = 8 
P.Q. Using an isometric dot paper, draw : 
(i) a cube with each edge 3 cm. 
(ii) a cuboid measuring 5 cm x 4 cm x 3 cm. 
Page 5


EXERCISE 31 
Question 1. 
Identify the nets which can be used to form cubes : 
 
Solution: 
Nets for a cube are (ii), (iii) and (iv). 
Question 2. 
Draw at least three different nets for making cube. 
Solution: 
 
Question 3. 
The dimensions of a cuboid are 6 cm, 4 cm and 3 cm. Draw two different types of 
oblique sketches for this cuboid. 
Solution: 
 
Question 4. 
Two cubes, each with 3 cm edge, are placed side by side to form a cuboid. For 
this cuboid, draw : 
(i) an oblique sketch 
(ii) an isometric sketch. 
Solution: 
 
 
Question 5. 
The figure, given below, shows shadows of some 3D objects, when seen under 
the lamp of an overhead projector : 
 
In each case, name the object. 
Solution: 
 
Question 6. 
Look at the solids, drawn below, and fill the given chart. 
 
Solution: 
 
P. Q. Using Euler’s formula, find the values of a, b, c and d. 
 
Solution: 
 
(i) a + 6 — 12 = 2 ?a = 2- 6+12 = 14-6 = 8 
(ii) b + 5- 9 = 2 ?b-2 + 9-5 = 6 
(iii) 20 + 12 – c = 2 ? 32 – c = 2 ? c = 32 – 2 ? c = 30 
(iv) 6 + d – 12 = 2 ? d-6 = 2 ? d = 2 + 6 = 8 
P.Q. Using an isometric dot paper, draw : 
(i) a cube with each edge 3 cm. 
(ii) a cuboid measuring 5 cm x 4 cm x 3 cm. 
Solution: 
 
 
Question 7. 
Dice are cubes with dot or dots on each face. Opposite faces of a die always have 
a total of seven on them. 
Below are given two nets to make dice (cube), the numbers inserted in each 
square indicate the number of dots in it. 
 
Insert suitable numbers in each blank so that numbers in opposite faces of the 
die have a total of seven dots.