Question

Find the radius of a sphere whose surface area is 154cm square. ​

Answer 1

Answer:

Surface Area of sphere =

$4\pi {r}^{2}$

Hence 154 = 4 × 22/ 7 × r×r

= 22= 4 × 22 ×r×r

22 will be cancel

So

4 = r×r

Hence r= 2

Answer 2

Answer:

$154 = 4\times 22 \div 7 \times r ^{2} \\ =154 \div 4 = 22 \div 7 = 38.5 = 22 \div 7 = r ^{2} = 22 \div 7 \times 385 \div 10 = r ^{2} = 121 = r = 11$

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