Agroup of 4 adults and 6 children paid 76$ for admission to the zoo another group of 4 adults. and 3 children paid 68$ how much should a group of 3 adults and 7 children pay for zoo admission

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?