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Calculate, correct to 3 significant figures, the circumference of a circle with: (i) radius 7 cm (ii) radius 10 cm (iii) radius 12 cm.

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Using C = 2 x π x r with π = 22/7 gives: (i) 2 x (22/7) x 7 = 44.0 cm, (ii) 2 x (22/7) x 10 = 62.9 cm, and (iii) 2 x (22/7) x 12 = 75.4 cm.

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1 Answer

  1. Formula for circumference is C = 2 x π x r, taking π = 22/7:

    (i) For r = 7 cm: C = 2 x (22/7) x 7 = 44 cm = 44.0 cm (to 3 significant figures).

    (ii) For r = 10 cm: C = 2 x (22/7) x 10 = 440 / 7 = 62.857… cm = 62.9 cm (to 3 significant figures).

    (iii) For r = 12 cm: C = 2 x (22/7) x 12 = 528 / 7 = 75.428… cm = 75.4 cm (to 3 significant figures).

     

    For more NCERT Solutions of Class 9 Ganita Manjari Chapter 6 Measuring Space: Perimeter and Area Question Answer (2026-27)

    https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-6/

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