(related to Proposition: 1.32: Sum Of Angles in a Triangle and Exterior Angle)
If two triangles have two angles in one respectively equal to two angles in the other \((\alpha_1=\alpha_2\), \(\beta_1=\beta_2)\), then they are similar, i.e. their remaining pair of angles is also equal \((\gamma_1=\gamma_2)\).
Proofs: 1