Step 1: Identify the dimensions from the figure.
Diameter of hemisphere \(= 6\) cm
\[
\Rightarrow r = 3 \text{ cm}
\]
Height of cone \(= 9\) cm
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Step 2: Volume of the hemisphere:
\[
V_{\text{hemisphere}} = \frac{2}{3}\pi r^3
= \frac{2}{3}\times 3.14 \times 3^3
= 56.52 \text{ cm}^3
\]
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Step 3: Volume of the cone:
\[
V_{\text{cone}} = \frac{1}{3}\pi r^2 h
= \frac{1}{3}\times 3.14 \times 3^2 \times 9
= 84.78 \text{ cm}^3
\]
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Step 4: Total volume of ice-cream:
\[
V_{\text{total}} = 56.52 + 84.78 = 141.3 \text{ cm}^3
\]
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Step 5: Using density \(= 0.9\) g/cm\(^3\), mass of ice-cream:
\[
\text{Mass} = 0.9 \times 141.3 = 127.17 \text{ g}
\]
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Final Answer:
\[
\boxed{126 \text{ g to } 128 \text{ g}}
\]
\bigskip