Class 7 Maths - CBSE
Parallel and Intersecting Lines
In the Class 7 CBSE chapter 'Parallel and Intersecting Lines', students explore the foundational geometric relationships between lines in a plane. The chapter covers the definitions of intersecting lines, concurrent lines, and parallel lines, alongside the special angle pairs formed when a transversal intersects two lines. Students learn to identify corresponding angles, alternate interior angles, alternate exterior angles, and interior angles on the same side of the transversal. Understanding these angle properties is crucial for board exams, as they form the basis for solving complex geometry problems and proving theorems in higher classes.
Start Learning FreeKey Concepts
Intersecting Lines
Two lines that meet or cross each other at a single common point are called intersecting lines.
Parallel Lines
Two lines in a plane that never meet and always remain at the exact same distance apart from each other are called parallel lines.
Transversal
A line that intersects two or more lines at distinct points is called a transversal line.
Corresponding Angles
Angles that occupy the same relative position at each intersection where a straight line crosses two others are corresponding angles and are equal when the lines are parallel.
Alternate Interior Angles
Pairs of angles formed on opposite sides of the transversal and in between the two parallel lines are alternate interior angles and are equal in measure.
Important Formulas
Board Exam Info
In CBSE Class 7 Mathematics, geometry chapters like 'Parallel and Intersecting Lines' typically carry around 8 to 12 marks in the final exams. Common question types include finding unknown angle measures using angle sum properties and transversal rules, identifying types of angle pairs from given figures, and proving whether two lines are parallel based on given angle conditions.
Frequently Asked Questions
How can we prove that two lines are parallel?
Two lines are parallel if a transversal intersects them such that any pair of corresponding angles are equal, alternate interior angles are equal, or interior angles on the same side of the transversal are supplementary.
What is the main difference between intersecting and parallel lines?
Intersecting lines cross each other at one common point, whereas parallel lines never cross or meet, no matter how far they are extended.
Are consecutive interior angles always equal?
No, consecutive interior (or co-interior) angles are supplementary, meaning their sum is 180 degrees, not equal, when the lines are parallel.
Learn Parallel and Intersecting Lines with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards