NCERT Solutions: Visualising Solid Shapes- 2 Notes | Study Mathematics (Maths) Class 7 - Class 7

Exercise 15.3 

Question 1: 

What cross-sections do you get when you give a:
(i) vertical cut (ii) horizontal cut to the following solids?
(a) A brick    
(b) A round apple    
(c) A die
(d) A circular pipe    
(e) An ice-cream cone.

Answer 1:

S.No.	Name of article	Figure	Vertical cut	Horizontal  cut
(a)	A brick
(b)	A round apple
(c)	A die
(d)	A circular pipe
(e)	An ice-cream cone

Exercise 15.4 

Question 1:

A bulb is kept burning just right above the following solids. Name the shape of the shadows obtained in each case. Attempt to give a rough sketch of the shadow. 

(You may try to experiment first and then answer these questions). 

Answer 1: 

S.No.	Object	Shadow	Shape's name
(i)	A ball		Circle
(ii)	A cylindrical pipe		Line
(iii)	A book		Rectangle

Question 2: 

Here are the shadows of some 3-D objects, when seen under the lamp of the overhead projector. Identify the solid (s) that match each shadow. 

(There may be multiple answers for these!) 

Answer 2: 

S. No.	Shadow	Shape's Name	3-D objects
(i)		Circle	Chapatti, Football, Disc, Plate etc.
(ii)		Square	Die, Square paper sheet, cubical magic box, Chalk box etc.
(iii)		Triangle	Ice-cream cone, Birthday cap, etc.
(iv)		Rectangle	Geometry box, Book, Table etc.

Question 3: 

Examine if the following are true statements: 

(i) The cube can cast a shadow in the shape of a rectangle. 

(ii) The cube can cast a shadow in the shape of a hexagon. 

Answer 3:

(i) True

(ii) False