Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 15 Visualising Solid Shapes Ex 15.3 Textbook Exercise Questions and Answers.
PSEB Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Ex 15.3
1. Count the number of cubes in each of the following figures :
Solution:
(i) 6
(ii) 21
(iii) 32
(iv) 13
2. If three cubes of dimensions 2 cm × 2 cm × 2 cm are placed side by side, what would be the dimensions of resulting cuboid ?
Solution:
Length 6 cm, breadth 2 cm and height 2 cm.
3. If we throw light an the following solids from the top name the shape of shadow obtained in each case and also give a rough sketch of the shadow.
(i) DVD player
Solution:
(ii) Sandwich
Solution:
(iii) Straw
Solution:
4. What cross-sections do you get when you given a.
(i) Vertical cut
(ii) Horizontal cut.
to the following solids ?
(a) A die
(b) A square pyramid
(c) A round melon
(d) A circular pipe
(e) A brick
(f) An ice cream cone.
Solution:
(a) Square, Square,
(b) Triangle, Square,
(c) Circle, circle
(d) Circle, Rectangle
(e) Rectangle, Rectangle
(f) Triangle, Circle.
5. If we throw light on following solids, from left name the shape of shadow in each and also give a rough sketch of the shadow.
(i)
Solution:
(ii)
Solution:
6. Here are the shadows of some 3-D objects, when seen under the lamp of an overhead projector. Identify the solids that match each shadow (There may be multiple answers for these)
Solution:
(i) Dice, chalk box etc
(ii) Book, Mobile, DVD Player etc
(iii) Cricket ball, Disc etc.
(iv) Birthday cap, Icecream cone etc.
7. Sketch the front, side and top view of the following figures :
(i)
Solution:
(ii)
Solution:
(iii)
Solution:
(iv)
Solution:
8. Multiple choice questions :
Question (i).
The number of cubes in the given structure is ?
(a) 12
(b) 10
(c) 9
(d) 8
Answer:
(a) 12
Question (ii).
The number of unit cubes to be added in above students to make a cuboid of dimensions 4 unit × 2 unit × 3 unit is ?
(a) 11
(b) 12
(c) 13
(d) 14
Answer:
(b) 12
Question (iii).
What cross-section is made by vertical cut in a cuboid
(a) Square
(b) Rectangle
(c) Circle
(d) Triangle
Answer:
(b) Rectangle
Question (iv).
What cross section is made by horizontal cut in a cone
(a) Triangle
(b) Circle
(c) Square
(d) Rectangle
Answer:
(b) Circle
Question (v).
Which solid cost a shadow of triangle under the effect of light
(a) Sphere
(b) Cylinder
(c) Cone
(d) Cube
Answer:
(c) Cone