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Visualising Shapes Exercise 19.1

Question: 1

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

Visualising Shapes Exercise 19.1

Solution:

  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.

Solution:

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) Pyramid: Christmas decorations, cheese and patio umbrellas.


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