In the adjoining figure, two triangles FGH and QPR are:
Similar using SAS criteria
In Δ FGH,
∠F=180∘−(∠G+∠H)∠F=180∘−(20∘+30∘)∠F=130∘In ΔFGH and ΔQPR∠F=∠QFGPQ=637=91 − − − − −(1)FHQR=455=91 − − − −(2)
(1) and (2) are equal
Hence, ΔFGH∼ΔQPR by SAS similarity.