Mayumi is constructing a line through point P that is perpendicular to RS←→. A horizontal line segment R S and a point P are drawn. The point P is above the horizontal line segment R S. She places her compass on point P to construct an arc. What must be true about the width of the compass opening when Mayumi draws the arc? It must be greater than 12RS. It must be equal to PS . It must be wide enough so that the arc intersects RS←→ in two points. It must be equal to PR .