Dixon and his little sister ariadne stand next to each other on the playground on a sunny afternoon. their mother measures their shadows. dixon's shadow is 18 feet long and ariadne's shadow is 15 feet long. if dixon is 6 feet tall, how tall is ariadne?

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?