Multiple choice

The area of a circle is increased by 44cm2 when its radius is increased by 2 cm, The original radius of a circle is?

  1. 1.5 cm

  2. 2 cm

  3. 2.5 cm

  4. 3 cm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Original area = πr². New area = π(r+2)² = πr² + 44. So π(r+2)² - πr² = 44 → π(r² + 4r + 4 - r²) = 44 → π(4r + 4) = 44 → 4π(r + 1) = 44 → r + 1 = 11/π ≈ 3.5 → r ≈ 2.5 cm.

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