The lines of CB=AD=4, B, E, C*** can be known by the vector multiplied by the number, so CE= 1/3CB=4/3. Similarly, you can also find the length of CF, the degree of known angle DAB, and angle ∠DCB= angle DAB, so that the three elements △CEF, CE, CF and ∞.

Point c is the point in the upper right corner.