Cone hat paper

For his birthday, George made a cone-shaped hat out of paper. The side of this cone is 35 cm long, and the radius of its base is 20 cm. How much dm of paper did George use to make it? Thank you

Final Answer:

x =  21.9911 dm²

Step-by-step explanation:

$$\begin{gathered} s=35\text{cm}\to \text{dm}=35:10\text{dm}=3.5\text{dm} \\ r=20\text{cm}\to \text{dm}=20:10\text{dm}=2\text{dm} \\ x=\pi \cdot r\cdot s=3.1416\cdot 2\cdot 3.5=21.9911{\text{dm}}^2 \end{gathered}$$

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