## Precalculus (6th Edition) Blitzer

$\left( 15,\frac{4\pi }{3} \right)$
Since it is given that the horse is in the outer circle, therefore r will be calculated as below: \begin{align} & r=6+3+3+3 \\ & =15 \end{align} The horse is $\frac{2}{3}$ of the way around the merry-go-round, therefore, the angle intercepted by the horse is given by: $2\pi \times \frac{2}{3}=\frac{4\pi }{3}$