# Hard SAT Math Question 74 — Video Explanation | 1600.now

Source: https://1600.now/hard/74

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74

An equilateral triangle with side lengths $3m$ is inscribed in a circle with radius $r$. Which of the following defines $r$ in terms of $m$?

A

$m\sqrt{3}$

B

$\frac{m}{\sqrt{3}}$

C

$\frac{\sqrt{2m}}{2}$

D

$\frac{\sqrt{3}}{2}$