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

Theorem 6.4 Deleted for CBSE Board 2025 Exams

Theorem 6.5 Important Deleted for CBSE Board 2025 Exams You are here

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 6.5 :- If a transversal intersects two lines, such that the pair of interior angles on the same side of the transversal is supplementary, then the two lines are parallel. Given :- Two parallel lines AB and CD and a transversal PS intersecting AB at Q and CD at R such that BQR + DRQ = 180 To Prove :- AB CD. Proof :- For lines PS DRQ + DRS = 180 But, BQR + DRQ = 180 From (1) & (2) DRQ + DRS = BQR + DRQ DRS = BQR 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