An equilateral triangle is inscribed in a circle. Find the ratio of diameter of a circle to the side of equilateral triangle.

Dear Student, 
Kindly refer to the link for the similar query.
https://www.meritnation.com/ask-answer/question/an-equilateral-triangle-is-inscribed-in-a-circle-of-radius-1/circles/6892047R

$$\begin{gathered} If Radius is 10 then diameter will be 20. \\ Also when radius is 10, side is 10\sqrt{3}. (Explained in the link mentioned above) \\ \frac{Diameter}{Side of equilateral triangle} =\frac{20}{10\sqrt{3}} \\ \Rightarrow \frac{Diameter}{Side of equilateral triangle}=\frac{2}{\sqrt{3}} \end{gathered}$$

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