(i) Here, figure (i) contains 7 faces, 10 vertices and 15 edges.
Using Euler’s formula, we see F + V – E = 2
Putting F = 7, V = 10 and E = 15,
F + V – E = 2 ⇒ 7 + 10 – 5 = 2
⇒ 17 – 15 = 2 ⇒ 2 = 2
⇒ L.H.S. = R.H.S.

(ii) Here, figure (ii) contains 9 faces, 9 vertices and 16 edges.
Using Euler’s formula, we see F + V – E = 2
F + V – E = 2 ⇒ 9 + 9 – 16 = 2
⇒ 18 – 16 = 2 ⇒ 2 = 2
⇒ L.H.S. = R.H.S.

Class 8 Maths Chapter 10 Exercise 10.3 Solution in Video

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