Multiple choice

The ratio of volumes of two sphere is 8: 27.The difference between the radius of first sphere and second sphere is 3 cm. What is the ratio of total surface area of these sphere respectively? दो गोलों के आयतन का अनुपात 8: 27 है। पहले गोले के त्रिज्या और दूसरे गोले की त्रिज्या में अंतर 3 सेमी है इन गोलों के कुल सतह क्षेत्रफल का अनुपात क्रमशः क्या है?

  1. 2 : 3

  2. 9 : 4

  3. 8 : 27

  4. 4 : 9
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Volume ratio V1/V2 = (r1/r2)³ = 8/27, so r1/r2 = 2/3. Given r2 - r1 = 3 cm. If r1 = 2k and r2 = 3k, then 3k - 2k = k = 3, so r1 = 6, r2 = 9. Surface area ratio = 4πr1² : 4πr2² = r1² : r2² = 6² : 9² = 36 : 81 = 4 : 9 after simplification.

Keep practicing — related questions