Theorems

Theorem 6.1

Theorem 6.6

Theorem 6.2 Important Deleted for CBSE Board 2025 Exams

Theorem 6.3 Deleted for CBSE Board 2025 Exams You are here

Theorem 6.4 Deleted for CBSE Board 2025 Exams

Theorem 6.5 Important Deleted for CBSE Board 2025 Exams

Theorem 6.7 Important Deleted for CBSE Board 2025 Exams

Theorem 6.8 Deleted for CBSE Board 2025 Exams

Chapter 6 Class 9 Lines and Angles

Serial order wise

Last updated at April 16, 2024 by Teachoo

Theorem 6.3 :- If a transversal intersects two lines, such that a pair of alternate interior angles is equal, then the two lines are parallel. Given :- Two lines AB and CD. And transversal PS intersecting AB at Q and CD at R, Such that alternate interior angles are equal. i.e, BQR = CRQ To Prove :- AB CD Proof :- For lines AB & PS AQP = BQR But, BQR = CRQ From (1) & (2), AQP = CRQ But they are corresponding angles. Thus, for lines AB & CD with transversal PS, corresponding angles are equal Hence AB and CD are parallel. Hence, proved