The RD Sharma Solutions for Class 7 Maths Chapter 14 Lines and Angles provides some very important topics for students to learn and use. Firstly, angle pairs are being discussed. They are the angles that appear together to display a certain geometrical property. Some of the angle pairs include Complementary angles, Supplementary angles, Vertical angles, Corresponding angles, Adjacent angles, Alternate interior angles, and Alternate exterior angles.
Adjacent angles have two angles with a common vertex and a common side but never overlap, whereas a linear pair is considered a pair of adjacent angles formed when two lines intersect. Next, there is an angle called vertically opposite angles. These are the angles that are opposite to each other when two lines cross, and they are always equal. Here, vertical describes the vertex, where they cross and not up and down. Secondly, angles at a point are being taught. A particular angle is measured concerning a circle with the centre at the common endpoint of the rays. The sum of angles at a point always makes 360°.
While talking about angle pairs, two angles are complementary when they add up to 90°. Therefore, they are not necessarily to be next to each other unless they make 90° to each other, whereas supplementary angles are the ones that measure up to 180°. In other words, the two angles can be supplementary to each other when their sum is equal to 180°. Additionally, any angle placed on the inside of a shape is known as an interior angle, and the angle placed outside of a shape is called an exterior angle.
Meanwhile, corresponding angles are formed in corresponding corners with a transverse angle when any different line intersects two parallel lines. Thus, transversals are capable of passing through two lines in the same point at two distinct points. Apart from all these, concepts like parallel rays, parallel segments, angles made by a transversal with two parallel lines, alternate interior and exterior angles are discussed in the chapter, along with many practise questions to ensure that the students retain these concepts in their minds.