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# RS Aggarwal Class 9 Chapter 7 Solutions (Lines and Angles)

RS Aggarwal Solutions for Class 9 Maths Chapter 7 uses the concepts taught in chapter 6 on Euclidean geometry and elaborates on many concepts around Lines and Angels. Our academic experts further make it easy for students to cram up all the basic as well as advanced concepts on the chapter with the step by step solutions.

In this chapter of RS Aggarwal Class 9 Maths Solutions, various terms and definitions on lines and angles are discussed with 52 questions spread across 3 exercises. We will learn about different types of angles like obtuse/right/reflex etc., angle relations and results on them, results on parallel lines, and axioms on corresponding angles. The questions are a mix of short answers where one has to find different types of angles and also define a few terms used with respect to lines and angles. There are questions with diagrams where one has to find the angles formed between lines.

InstaSolv’s subject matter experts write the solutions taking into account the standard, to which the problems belong. Hence it is very appropriate to the understanding level of students and students can easily go through the solutions which are explained in detail with every step building on the previous one.

## Important Topics for RS Aggarwal Solutions for Class 9 Chapter 7: Lines and Angles

The fundamentals of lines and angles in this chapter build a base for many high-level concepts that appear in the higher class. We will now see the highlights of this chapter as explained below:

• Angle – When 2 rays are starting from a common point, an angle is formed. The rays are called arms/sides/legs, and the common point is the vertex of the angle.
• Types of AnglesDepending on how the arms of the angle meet, different kinds of angles are formed ;
• Acute angleIf the angle formed is > 0o and less than 90o then it is an acute angle.

0o < θ < 90o

• Obtuse angle – If the angle formed is > 90o and less than 180o then it is an obtuse angle.

90o < θ < 180o

• Right angle – If the angle formed is = 90o then it is a right angle.

θ = 90o

• Reflex angle – If the angle formed is > 180o and less than 360o then it is a reflex angle.

180o < θ < 360o

• Straight angle – If the angle formed is = 180o then it is a straight line.

θ = 180o

• Complementary angles –
• Intersection lines – If 2 lines have a common point then they are said to be intersecting lines.
• Parallel lines – When 2 lines never meet each other i.e. there are no common points between them, they are called parallel lines.
• Some relations on angles – In this topic, you learn how angles are related to one another.
• Supplementary angles – If the sum of 2 angles is 180 degrees then they are called complementary angles.
• Complementary angles – If the sum of 2 angles is 90 degrees then they are called complementary angles.
• Adjacent angles – If 2 angles have a common vertex and common arms then the angles on either side of the common arm makeup adjacent angles.
• Vertically opposite angles – The angles which are opposite to each other in 2 intersecting lines are called as being vertically opposite to each other.
• Parallel lines and transversal – When a line intersects 2  or more lines at distinct points this is termed as transversal of the 2 lines which it intersects. The line which intersects these 2 lines forms 4 angles at each of the points of intersection
• Corresponding angles axiomThe angles made on the same side of the transversal are called corresponding angles. If 1, 2, 3, 4 are angles at the first point of intersection and 5, 6, 7, 8 or corresponding angles on the second point of intersection then:

∠1= ∠5

∠2= ∠6

∠3= ∠7

∠4= ∠8

### Exercise Discussions of RS Aggarwal Solutions for Class 9, Chapter 7: Lines and Angles

• The first set of exercises has 12 questions which revolve around definitions of types of angles and using your knowledge of relations of angles to find solve problems around it,
• The 2nd set of exercises has 16 questions in which you are needed to apply your knowledge of linear pair of angles, straight lines, vertically opposite angles and other relations between angles,
• The 3rd set has 24 questions involving transversal lines, corresponding angles axioms, rules related to parallel lines, types of angles and their relations.

### Benefits of RS Aggarwal Solutions for Class 9, Chapter 7: Lines and Angles

To get good marks, it is essential for students to solve all kinds of questions in maths which are possible with given RS Aggarwal Solutions

Sometimes students might find it difficult to grasp some of the concepts or sometimes they have so many assignments to do that they are unable to manage their time well. Instasolv solves all these problems by letting students practise extensively on helping them with simple and easily comprehensible solutions which not only enable students to do better time management but also equips them with the expertise to solve any kind of problem independently.

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