RS Aggarwal Solutions for Class 9 Chapter 13 "Geometrical-constructions", "Construction" in Geometry means to draw shapes, angles or lines accurately. These constructions use the only compass, straightedge (i.e. ruler) and a pencil. It is the "pure" form of geometric construction: no numbers involved! Geometrical Constructions are used by the architects to design a building with base, height and blueprint. It also has applications like mapping, navigation, surveying, calculates distances and astronomy. Chapter 13 has problems which are solved using some of the essential concepts like perpendicular bisector of a line segment and ways to draw perpendicular bisector of a given line segment and triangles.