Question 60

The total surface area of a hemisphere is 166.32 sq cm, ﬁnd its radius?

Solution

Let radius of hemisphere = $$r$$ cm

Total surface area of hemisphere = $$3 \pi r^2 = 166.32$$

=> $$r^2 = \frac{166.32}{3 \pi}$$

=> $$r^2 = 55.44 \times \frac{7}{22}$$

=> $$r^2 = 2.52 \times 7 = 17.64$$

=> $$r = \sqrt{17.64} = 4.2$$ cm

=> Ans - (A)

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