Ex 9.2, 12 - Chapter 9 Class 7 Perimeter and Area

Last updated at August 14, 2026 by

Ex 9.2, 12 - The circumference of a circle is 31.4 cm. Find radius - Ex 9.2

part 2 - Ex 9.2, 12 - Ex 9.2 - Serial order wise - Chapter 9 Class 7 Perimeter and Area

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Ex 9.2, 12 The circumference of a circle is 31.4 cm. Find the radius and the area of the circle? (Take Ο€ = 3.14) Radius = r = ? Given, Circumference = 31.4 cm 2πœ‹r = 31.4 2 Γ— 3.14 Γ— r = 31.4 r = (πŸ‘πŸ.πŸ’)/(𝟐 Γ— πŸ‘.πŸπŸ’) r = 314/10 Γ— 100/(2 Γ— 314) r = 1/10 Γ— 100/(2 Γ— 1) r = 10/2 r = 5 cm Now, Area of circle = πœ‹r2 = 3.14 (5)2 = 3.14 Γ— 25 = πŸ‘πŸπŸ’/𝟏𝟎𝟎 Γ— 25 = 314/4 = 157/2 = 78.5 cm2 ∴ Radius of circle is 5 cm & it’s area is 78.5 cm2

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