Parallel lines. On parallel lines, alternate (Z) angles are equal. ... are co-interior angles) Back to top. Test section. Question 1. What are intersecting lines? Show answer Hide answer.

The sum of interior angles in a triangle is 180°. To prove \(a + b + c = 180^\circ\), firstly draw a line parallel to one side of the triangle. \(d = b\) (alternate angles are equal) ...

Class 9 Maths Chapter 6 Lines and Angles is available here for download in PDF format. We have provided here the latest edition of the chapter which is published by the NCERT on its official website.

5. A transversal intersects two parallel lines as shown in the figure given below. Then which of the following statements is correct? (a) Each pair of alternate interior angles is equal.