Ceva's theorem states:
If the points D,E and F are on the sides AB, BC and AC of a triangle then the lines AE, BF and CD are concurrent if and only if the product of the ratios .
Applet
Drag the red point.
AD:DB = ABS:ACS, BE:EC = ..........
Check "Proof" and press "Next" button to understand Ceva's theorem.
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