Tree mesh

The farm provided around 150 fruit trees with a trunk diameter of 2 dm with mesh to protect them from wild animals. The mesh was placed so that it was 9 cm away from the trunk. How many regular meters of mesh were needed?

Final Answer:

n =  179.1 bm

Step-by-step explanation:

$$\begin{gathered} D=2\text{dm}\to \text{m}=2:10\text{m}=0.2\text{m} \\ r=D/2=0.2/2=\frac{1}{10}=0.1\text{m} \\ x=9\text{cm}\to \text{m}=9:100\text{m}=0.09\text{m} \\ {r}_2=r+x=0.1+0.09=\frac{19}{100}=0.19\text{m} \\ o=2\pi \cdot r_2=2\cdot 3.1416\cdot 0.19\doteq 1.1938\text{m} \\ n=150\cdot o=150\cdot 1.1938=179.1\text{bm} \end{gathered}$$

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