NCERT solution class 7 chapter 15 Visualising solid shapes 15.4 mathematics

EXERCISE 15.4

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Q 1, Ex 15.4 - Visualising Solid Shapes - Chapter 15 - Maths Class 7th - NCERT

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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:

The shapes of the shadows of these figures will be as follows.
(i) A ball

The shape of the shadow of a ball will be a circle.
(ii) A cylindrical pipe

The shape of the shadow of a circular pipe will be a rectangle.
(iii) A book

The shape of the shadow of a book will be a rectangle.

Q 2, Ex 15.4 - Visualising Solid Shapes - Chapter 15 - Maths Class 7th - NCERT

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Question 2:

Here are the shadows of some 3−D objects, when seen under the lamp of an overhead projector. Identify the solids (s) that match each shadow. (There may be multiple answers for these!)

Answer:

The given shadows can be obtained in case of the following objects.

1. Compact disk
2. A dice
3. Triangular pyramid
4. Note Book

Q 3, Ex 15.4 - Visualising Solid Shapes - Chapter 15 - Maths Class 7th - NCERT

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Page No 290:

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:

A cube can cast shadow only in the shape of a square. Therefore, any other shapes are not possible.