Answer: B
The height of the equilateral triangle = \(\cfrac{\sqrt{3}}{2} \times 2a = \sqrt{3}a\) cm ∴ The radius of the incircle of the equilateral triangle = \(\cfrac{1}{3} \times\) height = \(\cfrac{1}{3} \times \sqrt{3}a = \cfrac{a}{\sqrt{3}}\) cm
The height of the equilateral triangle = \(\cfrac{\sqrt{3}}{2} \times 2a = \sqrt{3}a\) cm ∴ The radius of the incircle of the equilateral triangle = \(\cfrac{1}{3} \times\) height = \(\cfrac{1}{3} \times \sqrt{3}a = \cfrac{a}{\sqrt{3}}\) cm