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Last updated at May 29, 2018 by Teachoo

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Example 3 Line-segment AB is parallel to another line-segment CD. O is the mid-point of AD (see figure). Show that (i) ∆AOB ≅ ∆DOC (ii) O is also the mid point of BC Given: AB || CD O is the mid-point of AD i.e. OA = OD To prove: (i) ∆AOB ≅ ∆DOC (ii) O is also the mid point of BC i.e. OB = OC Proof: AB || CD and BC is the transversal, ∠ABO = ∠ DCO Also, since lines AD & BC intersect ∠AOB = ∠ DOC Consider ∆ AOB and ∆ DOC. ∠ABO = ∠ DCO ∠AOB = ∠ DOC OA = OD ∴ ∆ AOB ≅ ∆ DOC So, OB = OC Hence proved

Chapter 7 Class 9 Triangles

Example 3
Important
Not in Syllabus - CBSE Exams 2021
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Ex 7.1, 3 Important Not in Syllabus - CBSE Exams 2021

Ex 7.1, 5 Important Not in Syllabus - CBSE Exams 2021

Ex 7.1, 7 Important Not in Syllabus - CBSE Exams 2021

Ex 7.1, 8 Important

Example 6 Important

Ex 7.2, 4 Important

Ex 7.2, 6 Important

Example 8 Important

Ex 7.3, 3 Important

Ex 7.3, 5 Important

Example 9 Important Not in Syllabus - CBSE Exams 2021

Ex 7.4, 3 Important Not in Syllabus - CBSE Exams 2021

Ex 7.4, 5 Important Not in Syllabus - CBSE Exams 2021

Class 9

Important Questions for Exam - Class 9

- Chapter 1 Class 9 Number Systems
- Chapter 2 Class 9 Polynomials
- Chapter 3 Class 9 Coordinate Geometry
- Chapter 4 Class 9 Linear Equations in Two Variables
- Chapter 5 Class 9 Introduction to Euclid's Geometry
- Chapter 6 Class 9 Lines and Angles
- Chapter 7 Class 9 Triangles
- Chapter 8 Class 9 Quadrilaterals
- Chapter 9 Class 9 Areas of parallelograms and Triangles
- Chapter 10 Class 9 Circles
- Chapter 11 Class 9 Constructions
- Chapter 12 Class 9 Herons Formula
- Chapter 13 Class 9 Surface Areas and Volumes
- Chapter 14 Class 9 Statistics
- Chapter 15 Class 9 Probability

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.