NCERT · Class 7 · Maths

Chapter 13: Visualising Solid Shapes

Practice each question, then open the answer or worked solution.

Exercise 15.4

Textbook page 289 · 3 questions

Q1Written answer

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).

(i)

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 61

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Worked solution

Solution:-

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 62

The shape of the shadow obtained from a ball is a circle.

(ii)

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 63

Solution:-

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 64

The shape of the shadow obtained from a cylindrical pipe is a rectangle.

(iii)

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 65

Solution:-

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 66

The shape of the shadow obtained from a book is a rectangle.

Q2Written answer

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

(i)

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 67

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Worked solution

Solution:-

Cricket ball, water bottle cap, Disc

(ii)

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 68

Solution:-

Die, chalk box etc.

(iii)

NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes Image 69

Solution:-

Birthday cap etc.

(iv)

Solution:-

Book, keyboard, mobile, etc.

Q3Written answer

Examine if the following are true statements:

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

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Worked solution

Solution:-

The above statement is true.

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

Solution:-

The above statement is false.

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Chapter 13: Visualising Solid Shapes

Exercise 15.4