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Multiple choice

Find the whole surface area of a cone of base radius 21 cm and height 28cm.

  1. 3696 cm2

  2. 4442 cm2

  3. 4244 cm2

  4. 9636 cm2

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Radius r = 21 cm, height h = 28 cm. Slant height l = √(r² + h²) = √(441 + 784) = √1225 = 35 cm. Total surface area = πr² + πrl = π × 21 × (21 + 35) = (22/7) × 21 × 56 = 3696 cm².

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