Chapter 6 Class 10 Triangles (Term 1)

Serial order wise

Last updated at Aug. 13, 2018 by Teachoo

AA Criteria If two angles of one triangle are respectively equal to two angles of another triangle, then the two triangles are similar.Given: Two triangles ∆ABC and ∆DEF such that ∠B = ∠E & ∠C = ∠F To Prove: ∆ABC ~ ∆DEF Proof: In ∆ ABC, By angle sum property ∠A + ∠B + ∠C = 180° In ∆ DEF, By angle sum property ∠D + ∠E + ∠F = 180° In ∆ DEF, By angle sum property ∠D + ∠E + ∠F = 180° From (1) and (2) ∠A + ∠B + ∠C = ∠D + ∠E + ∠F ∠A + ∠E + ∠F = ∠D + ∠E + ∠F ∠ A = ∠ D Thus, In Δ ABC & Δ DEF ∠ A = ∠ D ∠ B = ∠ E ∠ C = ∠ F ∴ Δ ABC ~ Δ DEF Hence, proved