Question 22Two circles are externally tangent. Lines $PAB$ and $PA'B'$ are common tangents with $A$ and $A'$ on the smaller circle and $B$ and $B'$ on the larger circle. If $PA=AB=4,$ then the area of the smaller circle is $1.44\pi$$2\pi$$2.56\pi$$\sqrt8\pi$$4\pi$
