Multiple choice

What is the area of the copper sheet required to prepare a cone of base radius 30 cm with the height 40cm? एक 30 सेमी आधार त्रिज्या और 40 सेमी ऊँचाई वाले शंकु को बनाने के लिए आवश्यक कापर की चादर का क्षेत्रफल ज्ञात कीजिए?

  1. 7543 cm2/सेमी2

  2. 5146 cm2/सेमी2

  3. 5432 cm2/सेमी2

  4. 7246 cm2/सेमी2
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A Correct answer
Explanation

For a cone with r = 30 cm and h = 40 cm, slant height l = √(r² + h²) = √(900 + 1600) = 50 cm. Total surface area (sheet needed) = πr(l + r) = π × 30 × 80 = 2400π. Using π = 22/7: 2400 × 22/7 = 7542.85 ≈ 7543 cm².

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