SURYAMG

Class 9 Mathematics — Chapter 6: Lines and Angles

Latest NEP-2020 & Rationalised Syllabus Aligned
info Syllabus Note: Under the rationalised syllabus, the triangle angle sum theorems (old Exercise 6.3) have been dropped. This lab focuses purely on the core concepts of intersecting lines (Exercise 6.1) and parallel transversals (Exercise 6.2).
explore Select a lab below to analyze intersecting linear pairs, parallel line transversal matching, or build a parallel mirrors laser setup!
Axiom 6.1 & 6.2 Engine
Intersection Plane
Lines AB and CD intersecting at point O
O A C B D
Vertically Opp. Pair 1 (∠AOC & ∠BOD) Vertically Opp. Pair 2 (∠COB & ∠AOD)

assessment Angle Measurement Lab

∠AOC (Indigo)
∠COB (Emerald)
∠BOD (Indigo)
∠AOD (Emerald)
Axiom 6.1: Linear Pair Check

∠AOC + ∠COB = 180°


Theorem 6.1: Vertically Opposite Check

∠AOC = ∠BOD

Try This: Click and drag the handles A or C on the canvas. Observe how adjacent angles always sum to exactly $180^\circ$ (supplementary), and opposite angles stay completely equal.