Points M and N are two of the vertices of a right triangle. They are the endpoints of the hypotenuse MN¯¯¯¯¯¯¯ of the triangle. The third vertex lies in the fourth quadrant. Plot a point at the location of the third vertex.

The triangle in the image below shows the RED line and 2 GREEN lines.
The RED line is the Hypotenuse MN
The two GREEN lines connect to form a right triangle to complete this triangle.
Point (5, -2) is the point on the fourth quadrant that is the third vertex of the right triangle.
ANSWER: (5,-2) is the 3rd vertex of the right triangle (graph shown)