Cho hai tam giác $ABC$ và $DEF$ có $AB = EF;\,BC = FD;AC = ED;$ $\widehat A = \widehat E;\widehat B = \widehat F;\widehat D = \widehat C$. Khi đó

$\Delta AMC = \Delta BCM$

$AM \bot BC$

$\widehat {BAM} = \widehat {CAM}$     

$\Delta AMB = \Delta AMC$

$AB = MN$ 

$AC = NP$   

$\widehat A = \widehat M$ 

$\widehat P = \widehat C$

50$^\circ$

40$^\circ$

70$^\circ$

80$^\circ$

$\widehat D = 33^\circ$ 

$\widehat D = 42^\circ$   

$\widehat E = 32^\circ$ 

$\widehat D = 66^\circ$

$\Delta ABC = \Delta CDA$

$\widehat {ABC} = \widehat {CDA}$        

$\widehat {BAC} = \widehat {DAC}$        

$\widehat {BCA} = \widehat {DAC}$

$\widehat A = \widehat D = 65^\circ ;\,\widehat C\, = \widehat F = 50^\circ .$

$\widehat A = \widehat D = 50^\circ ;\,\widehat C\, = \widehat F = 65^\circ .$ 

$\widehat A = \widehat D = 75^\circ ;\,\widehat C\, = \widehat F = 50^\circ .$ 

$\widehat A = \widehat D = 50^\circ ;\,\widehat C\, = \widehat F = 75^\circ .$