RD Sharma solution class 7 chapter 19 Visualising Solid Shapes Exercise-19.1

Exercise-19.1

Page-19.3

Question 1:

Complete the following table and verify Euler's formula in each case.
 

Faces (F)	6	4	9	7
Edges (E)	12	6	16	15
Vertex (V)	8	4	9	10

Answer 1:

	I	II	III	IV
Faces (F)	6	4	9	7
Edges (E)	12	6	16	15
Vertices (V)	8	4	9	10
Euler's formula (F − E + V)	6 − 12 + 8 = 2	4 − 6 + 4 = 2	9 − 16 + 9 = 2	7 − 15 + 10 = 2

Hence Euler's formula is verified for these figures.

Question 2:

Give three examples from our daily life which are in the form of (i) a cone (ii) a sphere (iii) a cuboid (iv) a cylinder (v) a pyramid.

Answer 2:

 Examples of

(i) Cone: Ice-cream cone, clown cap, rocket
(ii) Sphere: Football, a round apple, an orange
(iii) Cuboid: book, brick, duster
(iv) Cylinder: circular pipe, glass, circular pole
(v) Christmas decorations, cheese and patio umbrellas.