If the curved surface area of a hemisphere is 154 cm², find its diameter.
9.9 cm
Curved surface area of a hemisphere \(= 2\pi r^2\).
Using \(\pi = \dfrac{22}{7}\):
\(2 \times \dfrac{22}{7} \times r^2 = 154 \;\Rightarrow\; r^2 = \dfrac{154 \times 7}{44} = 24.5\).
\(r = \sqrt{24.5} \approx 4.95 \text{ cm}\).
Diameter \(= 2r \approx 9.9 \text{ cm}\).
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