Question

The radius of the circumcircle of an equilateral triangle of side 12 cm is

• A. (\frac{4}{3})$$\sqrt{3} cm
• B. 4$\sqrt{3}$ cm
• C. 4$\sqrt{2}$ cm
• D. (\frac{4}{3})$$\sqrt{2} cm

Answer 1

Answer: (B)

4$\sqrt{3}$ cm

Answer 2

From the question we know that, Side of the equilateral triangle = 12 cm

Area of triangle = $\frac{\sqrt{3}}{4} × Side^2$

= $\frac{\sqrt{3}}{4} × 12 × 12$ = $36\sqrt{3} cm^2$

Circumradius = $R = \frac{abc}{4 × area of triangle}$

= $R = \frac{12 × 12 × 12}{4 × \sqrt{3}}$

= $R = \frac{12}{\sqrt{3}}$

= $4\sqrt{3} cm$

The correct option is (B): 4$\sqrt{3}$ cm