RS Aggarwal Solutions Class 6 Chapter-13 Angles and Their Measurement (Ex 13D) Exercise 13.4

Before start solving the exercise question of Chapter 13 of RS Aggarwal Class 6 Maths book, it is good to have a quick overview of the concept, that is to say, a quick revision of the concept of Angles and their measurement.

In the subject of Geometry, one of the most important concepts for the students to understand is Angles. The word “Angle” is formed from the Latin word “Angulus” the meaning of which is ‘corner’ and hence the Angles itself deals with the corners of a geometrical figure. The amount of rotation found between the two different lines, which has originated from the same point, is known as “Angles”. In a simple language, when two different lines originate from the same point, there produces a space between the two, and that particular space is regarded as “Angle”. The measurement of this space is done using the degree, and hence the unit of measurement for the angle is degree. And in mathematical representation angle is presented by the symbol “∠” and hence instead of writing angle ABC, we should write ∠ABC. The formation of the angle is also possible by two curved lines.

An angle essentially has three parts, which are Vertex, sides, and Angle, interior, and Exterior.

• The common point where the angle is formed between the two different lines is called Vertex.

• The two lines which in order to form an angle, crosses are regarded as the side of the Angle, sometimes also, as the arms of angles.

• The space that is between the two lines is regarded as interior, while the space outside the two lines is called Exterior.

• And lastly, the angle itself, which is to say, the measurement of the space between the two lines.

Classification of Angles:

Angles can be classified on the type of rotation that the two lines have produced. There are basically six major types of Angles, which are Acute angle, obtuse angle, right angle, straight angle, reflex angle, and lastly full rotation angle.