Cylinder painting cost

How many kg of paint do we need to paint a cylinder with a diameter of 60 cm and a length of 2 meters if we use 0.5 kg of color for one square meter of surface? How much will we pay for paint if 1 kg costs CZK 165?

Final Answer:

m =  2.1677 kg
c =  357.6703 kc

Step-by-step explanation:

$$\begin{gathered} D=60\text{cm}\to \text{m}=60:100\text{m}=0.6\text{m} \\ h=2\text{m} \\ r=D/2=0.6/2=\frac{3}{10}=0.3\text{m} \\ \rho =0.5{\text{kg/m}}^2 \\ S=2\pi \cdot r^2+2\pi \cdot r\cdot h=2\cdot 3.1416\cdot 0.3^2+2\cdot 3.1416\cdot 0.3\cdot 2\doteq 4.3354{\text{m}}^2 \\ m=\rho \cdot S=0.5\cdot 4.3354=2.1677\text{kg} \end{gathered}$$

$c=165\cdot m=165\cdot 2.1677=357.6703\text{kc}$

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