In the diagram, $\triangle P Q R$ is right-angled at $Q, P Q$ is horizontal and $Q R$ is vertical. What are the coordinates of $Q$ ?
(A) $(5,2)$
(B) $(5,0)$
(C) $(5,1)$
(D) $(4,1)$
(E) $(1,5)$

![](https://cdn.mathpix.com/cropped/2024_04_20_6ed09463f225f8ba1f07g-086.jpg?height=349&width=377&top_left_y=1994&top_left_x=1297)
Since $P Q$ is horizontal and the $y$-coordinate of $P$ is 1 , then the $y$-coordinate of $Q$ is 1 .

Since $Q R$ is vertical and the $x$-coordinate of $R$ is 5 , then the $x$-coordinate of $Q$ is 5 .

Therefore, the coordinates of $Q$ are $(5,1)$.

ANSWER: (C)