Question

Find the volume or whose surface area is 15.4cmsquer

Answer 1

Answer:

Let the radius of hemisphere be a

TSA of hemisphere = 3 pi a^2

=> 15.4= 3 × 22 a^2 / 7

=> a^2 = 15.4× 7 / 66

=> a^2 = 63 × 7

=> a^2 = 9× 7 × 7

=> a = 3× 7

=> a = 21

Radius = 21 cm

Diameter = 2 × 21 = 42 cm

Answer 2

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Let the radius of the sphere be 'r' cm.

• Surface area = 4πr2
• 4πr2 = 154
• 4×22/7×r^2
• r^2=154×7/4×22
• =7×7/4
• (7/4)^2cm
• r=7/4=3.5cm

Thus, the required radius of the sphere is 3.5 cm.

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