γ

1


=

γ

2



⇔






|

A
C

|




|

B
C

|





=





|

A
D

|




|

B
D

|







{\displaystyle \gamma _{1}=\gamma _{2}\,\Leftrightarrow \,{\tfrac {|AC|}{|BC|}}={\tfrac {|AD|}{|BD|}}}