In the diagram, O is the center of a circle with radii OP=OQ=5. What is the perimeter of the shaded region?
The perimeter of the shaded region is \(10+\text{arc}(QP)\). The circumference of the entire circle is \(10\pi\). The arc is \(1 \over 6\) of the total perimeter, meaning that the arc's length is \({5 \over 3}\pi\). Thus, the perimeter is \(\color{brown}\boxed{10+{5 \over3}\pi}\)