Question 15In the diagram below, a diameter of each of the two smaller circles is a radius of the larger circle. If the two smaller circles have a combined area of $1$ square unit, then what is the area of the shaded region, in square units? $ \dfrac{1}{4} $$ \dfrac{1}{3} $$ \dfrac{1}{2} $$ 1 $$ \dfrac{\pi}{2} $
