RD Sharma Solutions for Class 7 Chapter 14 “Lines and Angles”, An angle is formed when two lines intersect each other. An angle involves two legs and one common vertex at which two lines meet. For example, Triangle AOD is formed when line AB and CD intersect with each other. It includes fundamental geometrical concepts like a pair of angles and their properties. The topics that are discussed include pairs of angles, adjacent angles, linear pair, vertically opposite angles, angles at a point, complementary angles, supplementary angles, parallel lines, corresponding angles, alternate interior and exterior angles and angles made by a transversal.