Class 9 Maths — Chapter 6: LINES AND ANGLES

What you'll learn

• ▸Basic Geometric Terms
• ▸Classification of Angles
• ▸Pairs of Angles: Complementary and Supplementary
• ▸Adjacent Angles
• ▸Linear Pair of Angles
• ▸Vertically Opposite Angles
• ▸Linear Pair Axiom
• ▸Vertically Opposite Angles Theorem

Chapter Summary

--- PAGE 1 --- CHAPTER 6 LINES AND ANGLES 6.1 Introduction In Chapter 5, you have studied that a minimum of two points are required to draw a line. You have also studied some axioms and, with the help of these axioms, you proved some other statements. In this chapter, you will study the properties of the angles formed when two lines intersect each other, and also the properties of the angles formed when a line intersects two or more parallel lines at distinct points. Further you will use these properties to prove some statements using deductive reasoning (see Appendix 1). You have already verified these statements through some activities in the earlier classes. In your daily life, you see different types of angles formed between the edges of plane surfaces. For making a similar kind of model using the plane surfaces, you need to have a thorough knowledge of angles. For instance, suppose you want to make a model of a hut to keep in the school exhibition using bamboo sticks. Imagine h…

Practice Questions from this Chapter

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1. Show real-world angle examples. Get Solution →
2. Explain parallel lines simply. Get Solution →
3. Discover lines in building designs. Get Solution →
4. According to the text, what is a part of a line with two end points called? Get Solution →
5. What is the exact measure of a right angle? Get Solution →
6. What is the sum of two complementary angles? Get Solution →
7. If three or more points lie on the same line, what are they called? Get Solution →
8. An angle that is greater than 180° but less than 360° is called a... Get Solution →

Did you know?

• 💡 The ancient Babylonians likely chose 360 degrees for a circle because it is easily divisible.
• 💡 Bees perform a "waggle dance" using angles to tell other bees where to find food.
• 💡 The Great Pyramid of Giza was built with nearly perfect right angles and straight lines.
• 💡 Although light usually travels in straight lines, massive objects can bend light's path.
• 💡 A straight line is the shortest path between two points only on a flat surface.

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