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CHAPTER AT A GLANCE
A Tale of Three Intersecting Lines
•Unit: Geometry
•Board weightage: Triangle inequality, existence and construction of triangles, angle sum property, exterior angle, altitudes and types of triangles give regular 1-mark, 2-mark, 3-mark and 4-mark questions (please check the latest sample paper)
•Key ideas from the textbook: constructing equilateral and other triangles with a compass, when a triangle exists, triangle inequality, constructions with two sides and the included angle or two angles and the included side, angle sum property proved by a parallel line, exterior angle, altitudes, classification of triangles
•Most scoring part: checking the triangle inequality with a conclusion, and finding angles by the angle sum property and the exterior angle property
•Time to revise: about 60 minutes
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