Measuring cylinder

A measuring cylinder has a base radius of 35mm and a height of 500mm. Calculate the surface area wetted by the liquid if the level reaches a height of 35cm.

Correct answer:

S =  808.1747 cm²

Step-by-step explanation:

$$\begin{gathered} r=35\text{mm}\to \text{cm}=35:10\text{cm}=3.5\text{cm} \\ h=35\text{cm} \\ {S}_1=\pi \cdot r^2=3.1416\cdot 3.5^2\doteq 38.4845{\text{cm}}^2 \\ {S}_2=2\pi \cdot r\cdot h=2\cdot 3.1416\cdot 3.5\cdot 35\doteq 769.6902{\text{cm}}^2 \\ S=S_1+S_2=38.4845+769.6902=808.1747{\text{cm}}^2 \end{gathered}$$

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