Multiple choice

The height of a cone is 21 cm. and radius of its base is 28 cm. Find its total surface area. एक शंकु की ऊँचाई 21 सेमी. है और इसके आधार की त्रिज्या 28 सेमी. है। इसका सम्पूर्ण पृष्ठ का क्षेत्रफल ज्ञात कीजिए।

  1. 4444 cm.2/सेमी.2

  2. 4642 cm.2/सेमी.2

  3. 5544 cm.2/सेमी.2

  4. 6655 cm.2/सेमी.2
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C Correct answer
Explanation

Total surface area of cone = πr(r + l), where l = √(h² + r²). Here l = √(21² + 28²) = √(441 + 784) = √1225 = 35 cm. Surface area = (22/7) × 28 × (28 + 35) = 88 × 63 = 5544 cm².

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