Answer :
It happens when you have 2 angles and 1 side in common at the same spot in two triangle at same time...
see the image...
Side
[tex]AC\equiv DF[/tex]
First Angle
[tex]A\^BC\equiv D\^EF[/tex]
Second Angle
[tex]B\^CA\equiv E\^FD[/tex]
see the image...
Side
[tex]AC\equiv DF[/tex]
First Angle
[tex]A\^BC\equiv D\^EF[/tex]
Second Angle
[tex]B\^CA\equiv E\^FD[/tex]