Toothpaste roll length

How long will the roll of toothpaste be extruded from the tube if the volume of the toothpaste is 100 ml and the diameter of the opening is 8 mm?

Final Answer:

x =  198.9 cm

Step-by-step explanation:

$$\begin{gathered} D=8\text{mm}\to \text{cm}=8:10\text{cm}=0.8\text{cm} \\ V=100\text{ml}\to {\text{cm}}^3=100\cdot 1{\text{cm}}^3=100{\text{cm}}^3 \\ r=D/2=0.8/2=\frac{2}{5}=0.4\text{cm} \\ V=\pi r^2\cdot x \\ x=\frac{V}{\pi \cdot r^2}=\frac{100}{3.1416\cdot 0.4^2}=198.9\text{cm} \end{gathered}$$

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