The line segment OP, which is the median, is what we call a perpendicular bisector. Since this line is a perpendicular bisector and it passes through the line segment MN, it divides the line segment into two equidistant points. Hence, line segment MP is equal to line segment PN. And from here, since the line segment OP divides the hypotenuse into two equal line segments, line segments MP and PN are half the hypotenuse of the triangle given.