Quadrilateral $P^{\prime}Q^{\prime}R^{\prime}S^{\prime}$ is similar to quadrilateral $PQRS$, where $P$, $Q$, $R$, and $S$ correspond to $P^{\prime}$, $Q^{\prime}$, $R^{\prime}$, and $S^{\prime}$, respectively. The measure of angle $P$ is $30^{\circ}$, the measure of angle $Q$ is $50^{\circ}$, and the measure of angle $R$ is $70^{\circ}$. The length of each side of $P^{\prime}Q^{\prime}R^{\prime}S^{\prime}$ is 3 times the length of each corresponding side of $PQRS$. What is the measure of angle $P^{\prime}$?