Triangles
Two triangular plots can look different yet be exact copies of each other. Chapter 7, Triangles, of the NCERT Mathematics textbook for Class 9 gives shortcuts for deciding congruence without measuring everything. You will prove the SAS, ASA, SSS and RHS criteria, apply them to riders with careful reasons, and then study inequalities that link sides and angles, such as the longer side facing the greater angle and the sum of two sides exceeding the third. Every claim is built into a proof.
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