
Alternate Angles
Last updated at July 24, 2025 by Teachoo
Transcript
Example 2 - Page 121 In Fig. 5.27, lines l and m are intersected by the transversal t. If ∠a is 120° and ∠f is 70°, are lines l and m parallel to each other? To check parallel, we first find corresponding angles And if corresponding angles are equal, then lines are parallel So, we can find Corresponding angle of a, i.e. ∠ e Corresponding angle of f, i.e. ∠ b Finding ∠ b Now, on line l ∠ a & ∠ b are linear pair ∠ a + ∠ b = 180° 120° + ∠ b = 180° ∠ b = 180° – 120° ∠ b = 60° Now, ∠ b & ∠ f are corresponding angles And they are not equal ∴ Lines l & m are not parallel