Canopy

Mr Peter has a metal roof cone shape with a height of 127 cm and radius 130 cm over well. He needs to paint the roof with anticorrosion. If the manufacturer specifies the consumption of 1 kg to 3.3 m², how many kg of color must he buy?

Correct answer:

m₂ =  2.25 kg

Step-by-step explanation:

$$\begin{gathered} v=127\text{cm}\to \text{m}=127:100\text{m}=1.27\text{m} \\ r=130\text{cm}\to \text{m}=130:100\text{m}=1.3\text{m} \\ h=3.3{\text{kg/m}}^2 \\ {s}^2=v^2+r^2 \\ s=\sqrt{v^2+r^2}=\sqrt{1.27^2+1.3^2}\doteq 1.8174\text{m} \\ S=\pi \cdot r\cdot s=3.1416\cdot 1.3\cdot 1.8174\doteq 7.4223{\text{m}}^2 \\ {m}_2=S/h=7.4223/3.3=2.25\text{kg} \end{gathered}$$

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