Master Chapter 5 Class 7 - Parallel and Intersecting Lines (Ganita Prakash) with comprehensive NCERT Solutions, Practice Questions, MCQs, Sample Papers, Case Based Questions, and Video lessons.
Start Learning NowWelcome to Chapter 5, Parallel and Intersecting Lines, from your Class 7 Maths book, Ganita Prakash.
This chapter is a fundamental part of geometry. It's all about what happens when lines meet on a flat surface (a plane)... and what happens when they don't!
We will start by exploring the simple, predictable rules that govern intersecting lines. When two straight lines cross, they meet at a single point and form four angles. You'll learn the key relationships between these angles:
Vertically Opposite Angles: The angles opposite each other at the intersection. You will learn why they are always equal.
Linear Pairs: The angles right next to each other on a straight line. You'll see why they always add up to $180^\circ$.
Perpendicular Lines: A special case where the two lines intersect to form perfect $90^\circ$ right angles.
Next, we'll explore parallel lines—lines on a plane that never meet, no matter how far they are extended.
The most important and powerful part of this chapter is what happens when we combine these two ideas. We will learn about a transversal, which is a line that cuts across two other lines (which may or may not be parallel).
When a transversal intersects two parallel lines, a set of special, predictable rules emerges for the eight angles that are created. You will learn to identify and use:
Corresponding Angles: Angles that are in the same "corner" at each intersection. We will learn the key rule: if the lines are parallel, these angles are equal.
Alternate Angles: Angles that are on opposite sides of the transversal and between the two parallel lines. You'll see that these are also equal.
Interior Angles: Angles that are on the same side of the transversal and between the two parallel lines. You'll learn why they always add up to 180°.
This chapter is like learning a new set of tools. Once you know these rules, you can solve all kinds of geometric puzzles, find any missing angle in a complex diagram, and even prove whether two lines are truly parallel or not.
These concepts are the building blocks for much of the geometry you'll learn in the future. At Teachoo, we'll break down each rule with clear, step-by-step examples to help you master them.
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