The side of an equilateral triangle is 9 cm. What is the radius of the circle circumscribing this equilateral triangle?

$2\sqrt{3}$ cm $5\sqrt{3}$ cm $4\sqrt{3}$ cm $3\sqrt{3}$ cm

$3\sqrt{3}$ cm

Formula to be used Circumradius = \(\frac{a \;×\; b \;×\; c}{4 \;×\; area}\) Calculations Circumradius = \(\frac{9 \;×\; 9 \;×\; 9}{4 \;×\; √3/4 \;×\; 9 \;×\; 9 }\) ⇒ \(\frac{9}{√3}\) = 3√3 cm Therefore, the correct answer is 3√3 cm.