Question 16Three circles of radius $1$ are externally tangent to each other and internally tangent to a larger circle. What is the radius of the large circle? $\dfrac{2 + \sqrt{6}}{3}$$2$$\dfrac{2 + 3\sqrt{2}}{3}$$\dfrac{3 + 2\sqrt{3}}{3}$$\dfrac{3 + \sqrt{3}}{2}$
