Intr-o cutie sunt bile galbene si rosii. numarul bilelor galbene este de 3 ori mai mic decat al celor rosii, iar diferenta dintre ele este de 18. cate bile din fiecare culoare sunt in cutie.

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?