Ruler case

A cylinder-shaped case is to be made for a ruler with the shape of a prism with a base in the shape of an equilateral triangle with a side length of 3 cm. What must be the smallest inner diameter of the housing? Determine the size to the nearest tenth of a centimeter

Final Answer:

D =  3.5 cm

Step-by-step explanation:

$$\begin{gathered} a=3 \\ r=\sqrt{3}/3\cdot a=\sqrt{3}/3\cdot 3=\sqrt{3}\doteq 1.7321 \\ D=2r=2\cdot 1.7321=2\sqrt{3}=3.5\text{cm} \end{gathered}$$

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